I fear he will seem superior, always

I am a college-going woman and have been dating a man four years older. He graduated a few years ago and works, so he always has more money than I do. This doesn’t affect our relationship much, but it leads to some resentment on my part because he always ends up having the upper hand. He gets to decide where we will meet on a date, what restaurant we will eat at, or how much we can spend if we go to a club. I know I will have more money when I start working too, but I am worried that the balance of power will shift to such an extent that it will always make him seem superior in some way. We have spoken about this, and he tries his best to be more accommodating, but it always feels like a losing battle. How can we make this easier on both of us?
You are already doing everything you can to find common ground. Financial issues are always tricky and need to be handled with sensitivity. The fact that you are both comfortable discussing it is a sign of maturity, and you should focus on the process more than the outcome because it displays willingness on his part to try and make this work. Your situation will change, as you point out, and so will the conversation when that happens. Until then, all you can and must do is point it out whenever you can so he is aware of any awkwardness. With time, you will both be able to navigate this a lot better.

My girlfriend recently asked me to meet her best friend, whom I ended up offending by saying something stupid. I apologised, but she has never forgiven me, and this has caused some friction between me and my girlfriend. How can I fix this?
You can meet them together and apologise again, if that helps, but your actions going forward will always help more. The only other thing in your favour is time.