Hello. Observe your plant and start noting all its characteristics.
Plant size
Smell
Weeks of flowering
Taste of the flowers
Detail everything very well in your diary, and at the end of your plant's cycle, you can compare with the genetics that Fast Buds has on their website. Good luck!
you might be able to narrow it down by smell/flavor... unless it's got some exotic colors, they often look a lot alike. Certain environmental variables will cause some additional variation too. Unless the attributes are unique and obvious, may only be able to narrow down to a few options in some cases.