Hi Tristin,
Welcome to Scuba Board. It's a great place to get good friends and advice. As far as going to a specialty store like your Local Dive Store or a department in a large sports store, it depends on how the store is set up. There are many sports stores that have a specialized scuba departments within their stores. Sort of a dive store within a larger store. Sports Chalet in California and Bill Jacksons's in Florida come to mind. For many, these are their LDS. Others have a scuba section, but don't treat it as a separate specialty. In this case, a separate store would probably be a better idea.
While there is a wealth of information both here and in reading material, and it's good to explore them as much as possible, go with your parents to the local dive stores and check them out. Find the one(s) that are the friendliest and most helpful. Don't be afraid to ask as many questions as you want. The staff should look forward to answering them. Same for your parents. It's important that they feel comfortable with the store also. Above all, you and your parents need to talk with your potential instructor(s) Again, you should feel good about the way they treat you and your parents should feel comfortable that this person is the one they want to trust teaching you. Believe me, this is a big issue with parents. Maybe your parents would even like to try a discover scuba class with you.
Don't get caught up with which agency the store uses. Despite numerous personal opinions you may read on which agency is best, the bottom line is that they are all good. Look for a good instructor, and when you find him/her stick with him/her.
Tristin, a big lifelong adventure awaits you. Please let us know how you make out, and how your lessons are going. Send us a few pics if you can.
Safe Diving
George
PADI MSDT 33859
Prime Scuba