Its totally wrong to marry a girl older than you. The reasons are:
1) Women are always very particular about age. They don't respect men that are younger than them. That explains the reason why there is always rivalry between a girl and her younger brothers
2) Women age faster than men. If you marry a girl than is 2 years older than you, as time progresses it will appear as if she is 10 years older than you! There will even be a time when everyone will think she's your mother!
Its totally not OK to marry a woman who is your mate or who is older unless you are ready to bear the consequences. A man ideally should marry a girl that he seniors with not less than 5 years.