Christina, don't give up! Like you, I'm 46, and although I've been a nurse for a while now (8 years) I remember what it was like being a student. First it was CNA classes, where they wanted me to be able to run as fast, lift as much weight, and care for as many residents as people two decades younger than myself; then college where I was doing projects with kids who had no concept of what it was like out there in the real world and relied on the one grown-up in the group to do all the legwork, and then nursing school
where expectations were higher for us older students, regardless of how much actual nursing
experience we had.
I made it through all of that, and so will you if you take the attitude, "If it's to be, it's up to me". Don't let the immaturity of some of your co-workers, or even some of your supervisors, get in the way of what you want. If you want to be a nurse, be a nurse..........no one can stop you but YOU.
Best of luck to you!