Measure twice, cut once
Just as in carpentry, making sure that your decisions are based on sound data is essential to reaching your goals. Ensure that you know precisely what is going to be required to make your dreams come true, and that you meet these criteria and are capable of the sustained effort necessary. For some goals, such as being a pitcher for the New York Yankees, a certain set of basic skills and physical attributes are non-negotiable. Making sure that you possess these skills and attributes before you put your house in hock to pay for a Major League baseball camp is only common sense. If you're unsure whether or not you have what it takes, ask someone who does know - but be choosy about who you ask. If you want advice about making the Major League, ask someone with that sort of inside info - a scouting-level college baseball coach, a sports agent, a sports journalist, etc. Don't ask cousin Bob just because he watches the game all the time and knows everyone's stats. Sure, he might be able to give you an unbiased viewpoint, but it is unlikely. Family baggage (he thinks you're the greatest thing since chipped beef, or he's still smarting over the fact that you ended up with "his" girl) can seriously impair his outlook. Friends and family members are usually the worst options for fair and objective evaluations, even if they are professionals in whatever field holds your interest. Only in the rarest of cases can someone be a professional first and a family member second - after all, they've probably been your (cousin, friend, etc) for much longer than they've been at their job.
That said, once you've double-checked the time, money and commitment necessary, and you're still sure you have what it takes - go for it!