Keep improving your velocity and try to be one of the top pitchers in your league. Get help in getting the word out to scouts. If you have pro-stuff, they will definitely take a look at you - especially a lefty with good stuff.
Important thing is that you improve because an 18 year old freshman lefty with the same stuff will be looked at much closer in terms of projectability than a freshman going on 21.
Good luck - you never know how much further your hard work will take you.