lots of good choices there to make a tree.
Satsuki usually won't bloom until May-June, though some early varieties will start in April. It will be a waiting game watching those buds continue to swell and grow. Enjoy. Let it bloom this year. Enjoy the flowers, begin ''bonsai work'' after it is done blooming. After blooming, give it a dose of fertilizer, let it rest 2 or 3 weeks, (meaning don't do any Bonsai techniques, just water and sun). Then start to work pruning and wiring. Or repot. Check out threads by
@Mellow Mullet