[Debaser]

You will not miss out tremendously if you just start from BG2 and play that and ToB.

However, I cannot think of anything more satisfying and completely badass (ESPECIALLY if you've never played the BG series before) than starting a character in BG and playing him through Tales of the Sword Coast, then importing him/her into BG2 and continuing. This will give you the ultimate role-playing satisfaction, and it is well worth it, my friend.