I think it is perfectly fine and there is absolutely nothing wrong with it.
In fact, I always have seem to gone for "older" women, and clearly remember being extremely attracted to a girl on the school bus (whose leg I used to always try to touch in a very light and subtle way as we got off the bus at the bus stop!) who was 2 years older than I from when I was 7-9 years old.

She was something else, and I wish I knew where she was now! I was even attracted to the Mom of the girl two houses down the street, I used to play with from as young as 4 years old!

In both of these cases, even though I was very young I had a "feeling" and would get "turned on", even though at that age I did not fully realize why this was happening.
And the woman who made a man out of me so to speak, was was 8 years older than me.
I was in a relationship for almost 5 years with an Okinawan woman who was 10 years older than me. For the most part, it was fantastic. Our age difference had very little (if any) reason for the break-up, which I always knew was inevitable due to other factors.
But anyway, if both people are approaching things on the same level it should be perfectly fine. Under no circumstances should the relationship or its validity be based on what anyone else thinks.