Too soon to be engaged?

My boyfriend and I havebeen together 9 months, and are thinking about getting engaged, and marrying in about 2 years after we've finished our Diplomas. We don't love together but have been making plans to move in together next year. We have excellent communication skills and work every argument out maturely (which is a good sign). I'm 21 and he's 20 and we have a very deep relationship. Based on the information I have just given, does getting engaged sound like a good idea?