Anyone who writes is "a real writer". Do you mean a published author?
There's really no way to tell, because you don't say what the prize was for. If it was for the closest possible copy to Dickens' writing style, then it means nothing - people don't buy new books written like that. If it was for a 200 word existentialist monologue...again, not much market for it.
If it was for something vaguely commercial, then it's a good sign - but still, 4 prizes just at your university just this year. How many Ivy League universities in the US - a dozen? Plus equivalents in other countries, and good writers who weren't good enough all round to get into an Ivy League...and that's just the people who are exactly the same age as you.
Congratulations on your prize. It will look great on any submissions you make in the future. But you need not to assume that you have it made.