I was 41 when I graduated nursing school. I didn't have trouble finding work.
I am deeply involved in onboarding in my current role. The physical condition of the applicant does matter. Age doesn't factor in; however, if the person doesn't seem fit enough or energetic enough to handle the job they are applying for, it is a factor. It bears noting that this has very little to do with weight/age and much to do with the energy the person brings to the table during the interview process.
I do not know you, so I don't know if this is a factor, but it goes without saying that older applicants often creak and moan more than younger ones simply by virtue of the realities of aging. Be sure you are portraying yourself with energy and enthusiasm. Bright eyes, bright smile, happy demeanor, engaged methods of speaking. If you are getting interviews and not getting selected, then it is due to something in the interview process. If you aren't getting interviews at all it is something in your resume, something about the positions you are applying for (ie: looking for experienced nurses not new grads), something in the geographical location you live in or something to do with the specialty you are trying to break into. You may need to broaden your horizons, have someone look over your applications and possibly do some mock interviews and get brutally honest feedback.