Anxiety over gc going on days out

you can probably tell I’m anxious by nature!) I was the same when my own kids were small but had control over their activities then.

Stop it now.
The key word is control.
You have to let your family live their own lives without interference, because this is what it is. My mother did similar, always insisting on knowing where and what I was doing and interrogating friends to find out if I didn't say. It continued after my marriage and children, became worse when I separated, and eventually I reunited with my husband in my forties and moved many miles away.
Sadly, it was a great relief to know my private life remained private.
I sometimes wonder if this is sometimes the cause of estrangement of adult children; too much involvement in their lives for the best possible reasons but a refusal to let go; the partner /spouse recognises it and rejects it.

If you’re worried now, well, it won’t improve as they get older, I’m afraid.

Parties, late nights out, going to the pub, walking home late at night, driving, being driven by friends…..

I have young grandchildren but there is little point getting anxious about everything they do. As time goes on there will be far more things they take part in one of mine is off on a residential school trip next week. Quite honestly they have their life to live with as many experiences as possible. Bad things can happen any time anywhere but 99% of the time they don't.
Are you usually so anxious about things in general or is it just this one thing.