what should I do for my birthday?

TL;DR Should I go to the zoo or thrifting for my b-day?

My birthday is in July which I know is far-ish away, but I'm a big planner especially things that I care a lot about. I'm turning 20.

I love thrifting but I also love the zoo. I get paid two days before and although I don't have a full idea of what will come out of that paycheck I should still have money to spend, regardless.

If I go thrifting, it'd be pretty much a copy of what I did for my 18th b-day, except instead of going with my dad and bf (now ex), I'd be going with my dad and best friend. She isn't big on thrifting because she thinks she never finds anything good, but has gone with me a couple times. Plus she gets paid the week before and isn't big on going out when it's not when she's getting paid. Me and my dad love thrifting. Then we'd go out to eat after, I haven't decided on a. restaurant but there's a good chance we'd go to one of my favorites, which my best friend doesn't like.

The zoo, we'd probably go with me, my dad, his "fiancee" (who I pretty much hate), my two year old sister, and my other sister who will be born in June. I'd pay for the tickets, but the idea of going with everyone including a one month old (in July no less) sounds like a bad idea. I don't want my sister to get sick or anything and I really don't want to deal with his "fiancee" complaining the entire time.

But we went in December, I paid for the tickets and since it was winter it was pretty cheap. But due to a mix of things we got there super late, like two hours before closing, and we only saw like a few animals. We stopped to eat at the cafe but we stayed for like way too long, and yea... I was super excited for the zoo and was obviously really disappointed so my dad said he'd make it up to me in the spring. But I don't know if he actually will or not so idk if I should just plan a visit for my birthday or not.

I can't talk to really anyone about it because my dad won't talk to me about my birthday since it's so far away and the only people I know aside from my family and best friend is my therapist and coworkers. I can try talking to at least other members of my family but they'll say to go thrifting because they also don't like my dad's "fiancee" or my therapist which I might but idk.

I have a couple other ideas for my birthday but I doubt anyone I know (myself included tbh) is going to want to go on a hike in July and a good majority of my extended family will be on vacation during my birthday so a party is out of the question.

Last year me, my dad, his "fiancee" and my sister went to the aquarium and then to my favorite restaurant which I did have a good time and greatful for it but it felt more like a family trip than my birthday, especially because my sister is two (well, she was 1.5 then) so she took up a lot of the attention, which I understand. It's just that a lot of times I feel excluded when I'm with my dad, his "fiancee" and my sister, mainly because of how his "fiancee" acts even though I have two other younger siblings and while I did get jealous with them, it was never like I feel in those situations. I'm just scared it'll turn into that again if we go to the zoo. I'm not saying everything has to be revolved around me, but not getting interrupted or talked over for like 5 minutes would be nice. Idk, the more I think about the more like an asshole I feel.