For a pitcher I'd really rather see you go through a few months of arm rest this time of year. Though it's not too early to do a showcase, something scheduled right at the end of your high school season, maybe in June, would be a better fit. It would allow you to be at your very best as you step further up in the process of trying to show yourself.
If someone with solid credentials knows you and would recommend you, a trip to PG's Junior National Showcase would be the best you could do at your age. If you can prepare yourself to gain some more heat as the weather warms through your spring season, that could well be in the cards for you.
Barring that, there are other PG events in June. Check their web site for a complete listing.