i am a relatively young nurse, in my early twenties. i currently only have 1+ yr experience compared to the many senior nurses i work with that have 25+ years of experience. i also look quite young (being 4'11" doesn't exactly help), so sometimes it seems like almost every shift i work i get a comment about my age from someone.
i definitely feel that i need to work hard to prove myself, sometimes to patients and sometimes to other nurses. patients will often ask how old i am or how long i have worked there and some of them seem to need reassurance that i am capable. fortunately, i almost always win them over by the time my shift ends. :) i find that other nurses are sometimes not so easy to win over. this is not to say that all of the nurses i work with underestimate me. in fact, i find the majority of them to be supportive and have confidence in my abilities, however, there's always the odd person that doesn't.
honestly, i find that since i make such an effort to be professional and mannerly, people usually come to see that i am, in fact, quite competent. but i've come to realize that some people just have the notion that "young people" in general have nothing to contribute or nothing worthwhile to say...because they are "young".
and i can't speak for what obstacles, judgements, criticisms and other negatives that older nurses face because i'm not at that point yet. i'm sure when i do get there, i'll find that there's a whole other plethora of issues and criticisms i'll have to endure.