Well, I would think that before you even consider marriage, you must have your heart prepared for it. So studying marriage within the bible and what marriage means according to God is very important. However I do believe it is important to prepare yourself at a younger age, perhaps early 20's, maybe sooner. Just for the reason that we have such little time left in this world that if you do not act, you may not be able to.
Also like Justcuz said, it really helps you fight fornication, so especially nowadays, it is important to get married if you feel like your fighting lust. However if you do not fight lust, Paul highly recommends in 1 Corinthians 7:7-9 that you remain unmarried and focus on pleasing the Lord, and not a spouse.
So it is very important to truly consider and think on marriage and what it means to God, and what you want from it before you even consider getting married, because marriage is something truly special and of the up-most importance, and should not be taken as something you have to do in your life, but rather something you can do to make your life more pleasing for God.