Hi OP I don’t have any fashion advice but I just wanted to say how well you’re doing at taking on board all this advice. Even though some of it is rather direct!
I am just a few years younger than you and I’m also reinventing myself, in my case after a divorce rather than a large weight loss ( though I guess you could say I’ve lost 16 stone of useless man).
Like you, I think I’ve got a reasonably contemporary everyday style - the barrel jeans/trainers/ boots /leather jacket look. But I’d be terrified to have to find formal wear , especially for such an important occasion. I completely understand that you want to look good for your son as well as for yourself.
I've enjoyed looking at all the links here, I think I was very stuck on what middle aged women wore to weddings the last time I attended a few, which was probably 15 years ago! And of course 65 is the new 45 😬
I have one suggestion about your colouring. It does sound like you’re a soft autumn, if you’re drawn to all these sludgy greens, golds, warms reds and blues.
Which definitely means that your hair colour is wrong - it’s far too cool, more suitable for a summer. One thing you can do is take some photos and upload them to ChatGPT and ask it to change your hairstyle and colouring to a a soft autumn.
I think that you are drawn to “ buttery highlights “ because you know that your hair is too cool. But it might be your low light that needs changed , not your highlights. And you might need more contrast rather than thicker highlights . But a good hairdresser will advise. They should be happy to book you in for a consultation first, before you commit to any changes.
As Pp have said , the style needs tweaked. Not a total change, just an update.
You can do the same chat GPT trick with make-up, as that will be off now too. It will either be too cool if it’s ok with your hair or clash with it , if it’s ok with your skin tone.
You don’t need a whole lot of expensive make up, whatever anyone tells you. Just the right colours in any high street brand, like boots / Maybelline / revlon. For me, having the right colour of eyebrows, eye liner and lipstick totally transforms me.
Im a summer and my daughter is a soft autumn . If we try each others lipsticks. it looks horrible, it’s an instant “ oh no thats terrible “. Even with colours that look very similar in the tube. It’s quite startling. My beautiful 20 something DD looks like she’s ill in my colours 😮.
Are your earrings and necklace gold or silver ? Good is usually best for warm season women.