You can probably shoot all you want. If it's private property the owner can tell you to stop. If it's public, you have no restrictions on shooting. The big complication comes in when you do something with those pictures like sell them, not when you take them.
Most of the time, parents are happy to have pictures of their kids and it shouldn't be a problem. Just warning you that there are some potential pitfalls.
You might ask if the league has an "official" photographer? Sometimes they have exclusive rights to sell photos. Or on a good day, maybe that could be you? :hail: It doesn't stop spectators or parents or friends from taking pictures, it restricts other professional photographers from selling photos.
If you are taking pictures of your cousin, for yourself or your cousin, you shouldn't have any problems. It's when the marketing comes in that everything gets complicated.
Have you considered a web page with the pictures on it. Reduced size, watermarked of course. Not as expensive as CDs. There are multiple free web pages, where you could host a gallery. Hand out business cards with the website on it. You can find a very good site for around $100 a year. How many photo CDs is that?
Use the equipment you have and see how you do. You don't have to have a $2000 lens to make good pictures and see if there's a market. Take the photos first, and if you can make some money, invest in better equipment as you make progress.
You might think about a digital camera to cut your expenses for the long run, once you get going.
Sorry to say, but for sports, digital is better for a number of reasons. Cost is a big one, if you are going to shoot high volumes of pictures. You can expect 1 out of 3 pictures to be throw aways, if you are shooting action.
Another third are probably going to be, not quite right, because you aren't shooting a sitting subject with a choice of lighting and controlling placement of all the content.
If potential customers have to wade through out of focus or blurred actions shots, looking for a good one, they will get bored fast. Only display the best images. It makes you look better and holds their attention.