Unless you get drafted by a major league baseball team right out of high school, I would suggest going to a college that has a good baseball program and get your education while playing baseball. If you are good enough to be a top collegiate prospect and get drafted while in college, then I would try to play professionally and you can always go back to finish your education should you not make it to the major leagues. There are many people that have a long, productive minor league baseballcareer, although to earn a living at baseball, one should at least make it to the Triple A level of the minor leagues.

I saw a show years ago when Mike Schmidt played, he visited the Philadelphia Phillies minor league spring training and there were around 100 guys from the lowest two levels of the minor leagues in a room. He talked to all of them saying how difficult it is to make the major leagues. He stressed the importance of education, sayhing that maybe 1 or 2 of you, on average will ever set foot on a major league field as a player. This is to guys who have already made it as far as the minor leagues.

A player shouldn't give up, but unless a top prospect, be realistic and make sure you get a college education.

If you are good enough to play in Major League Baseball, you should take the opportunity and play. Your arm may not have that speed three years or even four years after attending college. If you can get into MLB right after high school, you should go. You can always attend college later.
However, if you are good enough for college baseball, then you should play there and work and hope to make it in MLB after college. Most players go straight from high school, into the farm team system before they are invited into the Majors. The other two major professional sports, football and basketball, do not have a farm system. The colleges essentially serve that purpose. But baseball has its own. So if you can earn a college degree on your baseball skill, do it. Not many players come from the college baseball ranks to make it in the major league. But some do. Get the college degree, then pursue the baseball career.