Should I get a lighter ball?

Question
I'm a 21 year old male, I'm 5'10 around 190Lbs. I workout regularly and I'm pretty strong for the most part. I haven't been a consistent bowler but my girl friend and I have decided we want to bowl a lot and maybe join a league. I've bowled with my thumb out and curving the ball by flipping my hand 180 degrees. The Pro at the Pro shop said that a lot of teenagers do this. He recommended that I go with Tropical Storm ball (15Lbs) with Fingertips. But I've hated this ball so far, I feel that it takes way to much work and concentration throwing this ball. I have to also bend my arm because the ball feels way to heavy. What weight should I do? I feel that 13Lbs would be perfect for me.
Should I keep doing my old ways with the thumb?
or just get a ball around 14 lbs or 13 and learn with my thumb in?

Personally I feel that I should just bowl with my thumb out because that is what I bowl the best with... and have the most fun with.

Then maybe when I get older and have more help from pros or coaches they can teach me how to switch to the recommended way of throwing.

Thanks for your help.

Answer
Jean,
You have the potential to benefit from the weight, and obviously can control the ball physically. Unfortunately, you began enjoying the game with a way lighter ball, with a very contorted delivery (no one at a professional level rolls the ball without a thumb and has had consistent success, unless they use the other hand to help control the ball). You've taught yourself to muscle the ball, and are probably trying to do that with the much heavier ball.

If the ball fits properly, it takes much MUCH less effort to become much more consistent (a real asset in league play). But, I suspect the volatility of your old delivery was fun and enticed you to get more involved. Your old delivery on today's VERY EASY lane conditions, is a high risk high reward game. You'll have some very good games but also some terrible games.

The league idea, is a good one. It will offer a structure but, the handicap basis of most leagues provide a way for various levels of players to compete in one group. If you are looking to participate because of the potential for fun and consistent schedule (of a night out), go for it. If you might get frustrated losing a lot, you might want to give the new ball and a new style a shot.

"Bowling your best" as you mentioned, is the idea in league play. But, consistency is more highly rewarded than the occasional big game. Not sure how long you've rolled the new ball, but any major change (with the ball fit, weight, performance potential of the ball - and you've changed all three) will always cause your games to go down because of the uncertainty and inconsistency brought on by the change.

Your motivation should answer your question. If you're looking to screw around, have some fun and get together with your girl and friends, you might want to try something more along the lines of your old "style". If your volatile style leads to inconsistency and you feel like you pull down the team, you may want to give the new ball some time. (It's ideal to start your league fresh (with the new style), because as you improve you'll benefit from higher scores and  (for awhile) enjoy higher handicap. You handicap will go down, but your consistency and games will be improving and should make you more valuable to the team as the season goes on.)

You might want to seek out a coach for some basics, and for someone to help you unlearn what you were doing (the hardest part of changing your game). Thanks for the questions. Good luck and good bowling.