Loose. In answering your question... I exposed both of my kids early to different sports, but let themselves dictate which sports to try based on their interest level. They are 14 (girl) and 11 (boy) now but early on they both were playing soccer, baseball/softball and recreational bowling at different times.
Soccer fell by the wayside, and softball did also for the girl early on. But I never pushed and ultimately Emma wanted to rejoin softball again just a few years ago. She now is on the high school JV softball team.
For bowling, it was always just fun for them. J.R. took to it and wanted more, but I took it slow for several years. We bowled a lot of practice and he loved watching me bowl. He joined his first junior league last year's season (fall of 2008) and I probably should have let him join at least a year earlier. He loves the sport though and has a great swing and has loads of fun.
My daughter lost interest in bowling around 11 which was fine. She joined the junior league this year after watching J.R. have so much fun. They both love bowling in leagues and with the family now. My stepdaughter (21) and her boyfriend both joined into bowling also within the last year because everyone was having so much fun.
I guess what I am saying is, have them try now... and let them have fun. They can even lose interest for a bit, but if they learn fundamentals... and learn to love the game, they will come back to it. I wouldn't worry about them being small either. It is more learning the mechanics. If they learn the mechanics, they WILL be able to handle the ball and grow into heavier balls a lot more quickly because they know the proper mechanics.
Have fun, your kids are at a great age!
Storm Sync, NVD & a worn-out Widow for spares.
Career HG: 300 (3)
Career HS: 772
Career High Avg(09-10) 217.
15-16 Avg: 189
Last year? Not pretty. No high scores worth posting from 15-16. But good times ahead.