Ask her out if you like her. I'm much younger than her and the man I would like to go out with is much older than you, however in my instance things would be more complicated so I'll wait a while, but age is only a number and life is too short so ask her out :)
age isn't just a number, it is an indication of when parts of your body will cease to function, so shouldn't be ignored completely especially if you are teenager marrying a rich old man, when age can be very important.
I'm sure:) Actually the man I like is not that old (43) so I doubt he'll drop off the twig just yet, but he is quite well off by co-incidence ( and it is a co-incidence).