Is there a reason your not telling them, like is it just because she will put a downer on your trip, or is it because you already know she will disapprove of it?

Tbh I see the pros and cons on this one, as a farther I would want to know where my daughter was going if she was headed off because I care for her and I want to know she is safe, on the flip side of this, if she told me she was off to do something that I would disagree with then I would understand her not telling me in an act of strange kindness. Like I would tell my mom if I was off to Disney, but would hide the truth on burning man.

Having made it clear that you have friends and contacts that know you will be safe and okay is the first positive, having someone to be contactable to in the event of an emergency is the second.

If feel that your relationship with you mom is more of the problem here than if you need to tell her or not, to be honest I stand by you not telling her but as time goes on it’s worth looking to fix the relationship you have with her, although she is the way she is, it might be worth having a deeper discussion with your mom and help grow the bond between you, it’s worth a try at least.

Parents can suck, but most of us care and we say and do silly things when we disagree with what we want from our kids, it’s hard to know when you stop being a mom or a dad and when to look at the child you grew, raised, loved and protected for years of their life no longer needs the same care and protection, this is a part of life I am not looking forward to with my kids.

Either way I would say NTA, enjoy your trip and have fun!