I think age is just a number, and can be very easily overcome if the couple is compatible. However, one aspect in which age can become a factor is EXPERIENCE. If one partner is much older than the other, then he/she is probably more experienced in relationships  and life in general, and conflicts may arise because of that. But if both are understanding of the issue and try to work together then it can work out. 

I'm not always right, but I'm never wrong -Garfield