to think 25 year olds shouldn't be hanging around with 18 year olds?

I’m with you OP. I think it’s odd and I would be concerned

Seems fine to me. I started dating my DH when I was 19 and he was 25.

When my dd was 19 / 20 she met a 25 year old friend online. This was during the pandemic, so socialising was limited. They became very close friends and dd often went to stay overnight with her (probably against the rules then). I wasn't overly concerned, though I did wonder about the friend's motives. I thought they could be sexual but that wasn't it. But friend did turn out to be extremely controlling and dd eventually woke up to this and, after a huge bust up, refused to see her again. In person, this woman was very sweet and friendly but I am sure she had a personality disorder because she was very mean to dd on social media once she realised dd couldn't be controlled.

Not saying this is always the case of course but just one experience. Dd was an obvious "victim" back then. She struggled with friendships as a teen and at the time she met this woman had finished college and was unemployed. I'd say though that the experience was a good one in that she learnt a lot from it and now has healthy friendships (now 22). The friend also helped her get her first job.

2 of my best friends are 33 and 34 and I’m 41. I’ve never thought it was weird. We’ve been friends for years. Some of my other friends are in their 50’s. I don’t think age really matters

I would be concerned about grooming/exploitation. Workplace friendships with an age gap are different to a working adult befriending college students.

You’re joking right? I met DH at 18 and he was 25.

I don’t think it’s particularly weird. I had friends in lower years, friends in older years and friends much older outside of school. One of my friends was in her 40s, but we just got on and went for a coffee and a chat. We’re still friends now and no weird stuff to the relationship, it’s just a friendship and we enjoyed chatting and she was lovely at giving me gentle guidance as an older teen. I also had friends who were boys and girls. Unless there’s other issues like your dd suddenly having behavioural changes or turning up drunk/drugged or missing school, I wouldn’t see any reason to be concerned. Perhaps they just have particular things in common or share a similar sense of humour. Do you expect her to stick to her own age group in the work place? Lots of 18+ work and would find friends of older ages there, or in activities outside school.

I remember struggling to make new friends after moving back to my home town after university and my DDad suggesting I try to hang out with teenagers at my old sixth form college. It felt like really odd advice and I was younger than 25.

She's probably not a risk to your DD but I agree that it's an unusual grouping. A completely mixed aged group would be different though.

This would be normal in a workplace and you wouldn’t comment on it.

Why not? They're all adults....

How did they meet? When I was 18 and definitely after school there were older people in our group. You get to that age and it stops being so clearly defined in my experience. I was dating a 27 year old at 19.

I think if it was a boy, a lot of people would think it was rather weird too.

Because of the potential sexual element. Is that what you're worried about?

What exactly concerns you about this friendship?

18 year olds are adults, so are 25 year olds. It's more strange that people consider 18 year olds to be children who should only be friends with other 18 year olds. When your an adult you can have friends of any age.

Even if it is weird what is the actual problem? Do you think she has an ulterior motive?

I agree that it's odd. Some people here are talking about having friends considerably older than them, but when you're only 18, the gap between 18 and 25 is huge!
If I were 25 and hanging around with 18 year olds, I'd wonder where I'd gone wrong.

Well my 17 yo dd is in the forces and has friends who are 17-30.
They're all young adults (she is frustrated she can't go out drinking though!)

When I was 16 to 18, I was dating 24 year old to about 26. Mom said no to 30+ I was very mature for my age and high school boys were just too immature. We lived on an Air Force base so dated some airmen and guys I met through jobs. Older guys had jobs, cars etc. NONE of them tried anything with me. All great guys. I later ending up marrying someone just a month older than me.

My 18 year old son had friends ( boys and girls) round for a bbq tonight. The ages ranged from 17 to 22. My daughter, 25 happened to be home and so she joined them. I was sat in another room and at one point could hear them all talking about what their experiences of lockdown were and comparing the impact dependant on their age. I think it's good to have friends of different ages and although this girl is older maybe she shares interests with this group? People do mature at different rates so she may just feel more comfortable with younger friends. What does you daughter say they do together? I'd check she isn't "calling the shots" in case she likes to boss younger ones about!

When I was 15/16, I had a few friends in their 20s as in the 80s, 15 year olds could get into pubs and clubs. My mum wasn't happy about it but I'm 51 now and I'm still friends with these people. Spoke to one of the guys today.
My daughter is 24 and my son is 18. They socialise together a lot - some of his friends, some of whom are young women are and in sixth form, are friends with my daughter and her friends so I guess that would be the same as your scenario. I don't think it's strange at all. I think it's a good thing that both of my children have friends of different ages and sexes.

It was club 18 - 30 !!

When I was 18 I had friends of all ages. It’s really not weird at all. At 18 you stop hanging out with people based on age - you’re an adult now. Do you only have friends who are your exact age too?

It's very weird. Once you finish uni, start working and making friends on a similar wavelength, why would you want hang around a bunch of teenagers (unless they're your younger siblings or cousins)? What do they talk about?

This is weird. I am 28 and 18 year olds have felt like a different species since I left uni at 22.

YABU. It's not a hugeee age gap in the grand scheme of things. I made friends with a 27 year old when I was 21 (22 now).