No, there's nothing ethically wrong with dating someone that much older than you. It's unorthodox, and some might say it's creepy, but we like who we like. Unless you're trying to steal the guy from someone else, there's nothing essentially wrong with it.
To me the real problem with these kinds of relationships isn't what other people think of them--screw 'em, it's your life--but that they don't usually work out. People of 47 and 22 don't have a lot in common, and I think that the age difference often ends up being a bigger obstacle than people expect. Your life experience, your goals, your entire outlook are vastly different in your early 20s and late 40s. But as usual, there are always exceptions, and no one should forgo pursuing something they really want just because it might not work out.
This could all be moot, of course. It doesn't sound like the guy is aware of your interest. If and when he is, it will be his job to decide how dating you might affect his daughter. You are thoughtful to consider her feelings, but it's really up to him. If he thinks it will offend her too much, I'm sure he will say so. There's nothing disrespectful about wanting to date him just because his daughter is your age.
Thanks for the question.
I just read a REALLY REALLY interesting article on men/women perspective on age differences. And Cary's right. I think we all think love is enough, but its not. Same goals, outlook on life, values will be what will guide you guys. I mean what if you turn 30 and want kids someday, but hes way past that. Hes probably a grandpa by then. You will resent that and a drift in age/perspective will tore that relationship apart.
You have to be realistic, even if the initial attraction seems to be very promising.
On a side note, Ive always been attracted to men somewhat older than me, but have come to realize that their lifestyle/outlook on life is far too different from mine and I cant allow myself to lie to myself that it will work.
Also....small note: even though studies found that many relationships (as well as MANY affairs ) start at work places, I suggest avoiding dating co-workers. But to each their own.
Good luck.
If you're saying you don't want to offend HIM that leads me to believe that you aren't receiving any positive signals from him. I would proceed with caution. You don't want to embarrass yourself in the workplace if he is not interested. Remember that you will be working in the same building and probably collaborating from time to time. You don't want to create an awkward position for yourself either.
rule of thumb:
the lower age limit to date is 1/2 your age plus 7 years.
If he is 47, the youngest "appropriate" woman he can date is 30 1/2. forgetaboutit! (wish I remembered where I read this rule of thumb. I think it is a hoot!)