If you're after only seedlings, you can mail order them from many sources. Some folks sell them on Ebay, Etsy, etc. BC are extremely easy to grow and develop, BUT with seedlings this size, the initial part of that is just allowing them to grow. Around here you can plant them in the ground for five years to develop trunk size and character, then dig them up (dig is misleading, you take a pruning saw and saw off all of the roots a couple of inches down) Then replant in wet soil to reestablish root. This process is best done in the spring.
TBH, this seedling isn't worth the trouble of ground layering and may be too young for the process at this point. The trunk isn't big enough to take the damage.
FWIW, most folks who like BC start with established larger trees. Containerized from a nursery is a great start. Meadows Farms nurseries have them, as do many nurseries in the N. Va. area. probably in Fredericksburg too. You can go as large as you want from those sources (BIG ball and burlapped trees, although expensive, are also fair game). Depends on what you want to do.
Also, I began BC bonsai with a large collected stump I bought from Zach Smith at
Bonsai South bonsai nursery 25 years ago. I've been very happy with it.
Not cheap, but buying a larger BC trunk pays off sooner than a seedling. BC are almost impossible to kill--overwintering can be an issue, but with proper protection, it's not a deal killer.