2.5 year old aggressive in park today

[WasntSupposedToBeLikeThis]

I have a 2.5 year old cockapoo who has always been a very gentle girl. No problems with other dogs. Mostly just ignores them. In the park this morning and for the first time ever she bared her teeth to another dog. The dog came over for a sniff. He was very gentle and my girl just started barking and snarling at it really angrily. She has never ever done that before. Should I be worried.

I would be. But only in the sense that any behavioural change is worrying.

Worth a trip to the vet to rule out anything pain related.

But you should consider how you can handle this in the future (not letting other dogs greet her etc) and keep an eye on her body language to avoid putting her in a situation where she might be made uncomfortable. Dogs really don’t need to greet other dogs, so incidents like this should be perfectly avoidable in the future now you knows she’s not necessarily happy.

Tbh she could just have finally lost her cool - ignoring other dogs when they greet her is her telling them and you she’s not interested. Being bothered on walks when she’s not interested in other dogs must be very irritating for her!

My dpuppy was awful yesterday.. I blamed the weather!!

Agree with @TheHungryHungryLandsharks . Vet check to rule out pain would be sensible but it’s really not uncommon for dogs (especially girls) to become ‘dog selective’ once they reach maturity. Avoiding putting her in situations where she is pestered by other dogs is key here. If she feels you advocate for her, she’ll be much better. If you keep setting her up fur unwanted attention she’ll learn to habitually take matters into her own paws

Is she spayed? If not, maybe she’s coming into season and was telling the other dog to jog on. It’s known.

Also bear in mind what you saw was communication between dogs, not aggression
Dogs tell each other to get lost like this all the time. It doesn’t mean they are aggressive. In the same way as someone coming into my personal space (especially a stranger) out and about would be met with a firm verbal response and body language, your dog was simply making a point

Perhaps she’s finally plucked up courage to stand up for herself!

Dogs are also like humans in some ways and are fully entitled to simply not like another dog, same as we are! Only we don't have to ( usually) actually bark and snarl to make it known! :-)

It took me a while to learn to advocate for my dog and physically stop other dogs approaching her (rather than letting her deal with it).

I felt a positive shift in our relationship when i started doing that.

The tricky bit it stopping a dog who isnt wearing a collar! Which happens more often than I would have imagined!