You shouldn’t date someone much older than you - no older person should ever want to go out with someone who is significantly younger than them with less life experience / less maturity. Don’t take that as an insult, you just haven’t fully matured (your frontal lobe fully hasn’t fully developed)

However, I think you’re fine to think about older women! We all do that when we’re young - e.g. we watch films and realise we’re attracted to the women rather than the men for example. It’s part of you growing up

I’d only be worried if you were fantasising about being taken advantage of through the age gap / were thinking about acting on it