Hey, there! (He isn't one of my pronoun sets, but I know you were just guessing based off previous interactions, so I'm not bothered. I don't remember anyone's pronouns here off the top of my head either, lol.)
What I am proud of is that you took the time to assess how you were feeling and were able to make a decision for yourself about what you wanted to do rather than what it felt like other people would want you to do. =) It can be hard to listen to our own voices when society's voice is so loud and when our parent's voice is so loud! So I am proud that you made a decision for yourself, regardless of what that decision was! I am also proud that you are happy with your decision and not beating yourself up for making it.
As for condoms size, there are size charts out there of what size to buy based on length and width of erect penis, but I don't know how consistent those are across different brands. Largely, it's going to be up to the person wearing the condom to assess if the size is right. Signs a condom is too big and they need to go down a size would be the condom slipping and sliding around and not really staying put as well as generally feeling a little loose. Signs a condom is too small and they need to go up a size are the condom cutting off circulation, the condom leaving a mark, and the condom causing a decrease in hardness that isn't regained. The condom should fit snugly but not feel like it's strangling anything.
A little bit of lube can go a long way, so 5 oz can last many couples a couple of uses, but how long the bottle lasts will depend on what you're doing and how much you need to use each time. =)