lion,
I don't know about an optimal age. I think any player could benefit it at any age. For us, we felt our son could handle the trip (being away from family and managing the various airports) since we wouldn't be there with him. Also, this trip for us wasn't about college exposure or baseball really (although the coaches are top notch and I'm sure they'll provide excellent references), it was about the trip. If he had done this trip on his own (without the baseball opportunity), it would've cost twice the amount he spent. Again, I encourage anyone whose interested to do it. This is an excellent organization and fantastic experience.