I wouldnt worry too much about your age. Some girls like TFs example like the idea of being with a much older man, these sorts of girls tend to be abit more mature for their age, open-minded and more secure within themselves. Whereas other 18 year old girls still have abit more growing upto do, they're much more susceptible to decision-making forced upon them by social and peer-pressures etc. Perhaps even finding a 10 year age gap at that age as 'creepy' even. As you get older however a 10 year age gap at say 25-35 is considered much more acceptible to most.

Also perhaps worth bearing in mind alot of young girls can be intimidated by the older man feeling inferior to him. I remember being 18 and feeling intimidated by people beyond their mid-20s as I felt they had much more life experience, wisdom etc that I just didn't possess at that time. I also (perhaps wrongly) thought people at that age 'had their shit together' career-wise, financially, in terms of relationships etc and me as an 18 year old kid not really knowing what I wanted out of life felt very much distant from that reality.