when u feel u are ready to settle down with the person you really care about, have a decent job to provide for you and your family, graduated from school, mature,and love yourself before you can love someone else. then you are ready to get married. and u will know when its your time to be married to that special person :)
You want to get to know the persons every side...and you should be out of college and already have a job/sturdy life plan. Age is just a number...you really just need a job, sturdy life plan, and a college degree. I'd say that happens at around ages 24-26. The best things come to those who wait, don't be stupid.