Had my first "no" experience with someone asking me to be a bridesmaid

I think I handled it as best I could. I really never thought I'd be in that situation but I had always told myself that I wouldn't be a bridesmaid for anyone just because, even if they made everything affordable. I just think we really aren't close at all. My FH is going to be the best man but that's because they work at the same place, carpool, and generally they hang out and get projects around the yard done a lot. I am not close with the fiance and we really don't talk at all. She wanted to fill a spot and said everything was going to be affordable. But with our own wedding and then the madness isn't really going to stop after October. We are needing to get a new house, I need a new job still, I need a vehicle, I have student debt to pay off come November. I explained this, that I have a lot to get straight and that obviously we will be there but I can't be a bridesmaid. I thought I would say that I don't feel comfortable because we aren't close, but I left that part out.