If you are 19 there are a few options for you:
1. If you really are that talented you go bug some team, but that's not a good idea
A better idea would be to find a community college or junior college with good coaches and a baseball team. If you work extremely hard or not only baseball and grades you can move from those colleges to a bigger university. Unfortunately you are too old for high school, so this is your best option. It's going to take a lot of sacrifice. If you don't intend on a baseball future you can still do the same thing and just not play for the school team. There are also baseball academies. You can google search these things.
Hope this helps.