New to real estate investing and have a few questions

Hello everyone i am currently in the military and 20 years old, i have 2 years left and i want to take advantage of the time i have left. i am currently looking into duplex’s - quad plexes in my area but haven’t found a deal that would make sense. should i only be looking at these type of multi-family property’s ? or could i also start of with just a single family property ? and if so what type of single family property? i also want to be able to obtain property’s the most efficient and fastest way i can. i am willing to learn and practice whatever it is that will be needed to obtain that goal.