Um, my husband brought up marriage to me and we had only known each other like a month and a half! to be honest, his parents brought it up first b/c they knew he was already thinking it.
We got married about 11 months after our first date. We have been married going on 8 years now.
Now is the time to plan for your future. If you two are comfortable with each other, I'm amazed that you guys haven't talked about where you are heading yet. Who knows, he may be the kind of guy who never wants to get married or have children! That happened to a friend of mine who waited for several years for the man to speak up, and when he finally it, it was to tell her that he planned to be a bachelor.
You don't need to go proposing to him, but you do need to figure out what you want together. Just straight up ask him what his plans are, that you would love to get married and start a family within the next year or two and what his goals are.
Seriously, on my FIRST date with my husband, we asked each other what our 5 year plan was. Our plan was the same, to be married and have a child or two and be finishing up with college. That took the pressure off just by asking what our goals and plan was for ourselves, not necessarily with each other.
However, marry him because you love him, not just because you want to get married soon. It has to be the right guy, who will cherish you forever, who will also make an excellent father, who yearns to be a father some day.
He may not be ready for marriage, just yet, but if he isn't interested in the idea, then tell him goodbye so you can start fresh. There is no point wasting your time on someone who doesn't want to end up with you in the long run, or have similar goals as you.
Good luck!