And remember, most bonsai are not started by seed. Most of us start with trees several times larger than the final envisioned size bonsai. For example, if I want a meter tall bald cypress, I would probably start with a 4 or 5 meter tall bald cypress and cut it down to half a meter tall, then regrow some height to its finished height. This is the way to get the large caliber trunks we like in bonsai. Growing from seed can be done, but then it can take a lifetime growing to get the caliper of trunk we would like.
Ficus are good for bonsai. You can find trees ready to be cut back and styled. No waiting for it to "grow up" first.