Is it normal for a middle-aged woman to think about young guys when having sex?

I'm in my 40s, my husband is 50, and we still have sex quite often. I'm English but now we live in France, and I work as changing room attendant at a sports centre. In France this means I have to take care of the men's side too. Weekdays, our pool and gym are used by local high schools and colleges, and everyone without exception showers afterwards, and is naked around the changing room, getting weighed, etc. So, I get to see lots of males aged 14-20 naked every day, and I do like to take a good look at the good-looking ones, their penises and bare bottoms. Then at night, when having sex with my husband, I find myself thinking about those guys, and it brings me to a climax easily. Is this normal?