College and Showcases for High school

hey guys whats up. I was wondering if i could get some info for some showcases for high school and college. I live in Cananda and ya not too many show cases here.

Anyways i was considering crossing the border and going to a few in the United States. My question.

Do you have to get invited to go to a showcase or a camp or can you go and tryout.

Some showcases say for high school and some say for college. Would i get embarrased if i went to a high school show case grade 9-12. And i was throwing around 80mph. LIke would all kids their be throwing like 90mph or would they be throwing like 75-85mph.

I would like some info please. Because i really really want to continue my baseball career because i love the game.
I am still a sophmore and i would love to go to a few show cases or camps this year in the states and probaly alot more when i reach my senior year in high school. I just am trying to get my name out to coaches and scouts. Thanks for reading this guys.