Awesome!! I think its a great way to get into reptiles. Dragons are fun and you will fall in love immediately.
Make sure your set up and food are at your house before you buy a beardie.
You also said biting will freak you out and you might drop the beardie. Sometimes juvi's to teenagers can be a little frisky and puff out and attempt to bite. Its usually just a phase so you need to choose a dragon from a reputable breeder that handles there dragons quite a bit. Research the breeder first. There are a lot of bad ones out there and they are hard to tell from the good ones. So research everything about your dragon and its enclosure way before you even spend any money.
This is the best place to come for help and information. You will love love love love love a dragon.
Make sure your mom fully understands the responsibility and cost. NEVER EVER take the advice of a pet store worker even if they claim to own a zillion dragons.
There are always bearded dragons in desperate need of a good home on your local craigslist. That may be a great way to get a new buddy.
CONGRATS AND GREAT CHOICE.