I'm not familiar with the
root system of the Chokeberry, but many shrubs and
trees have a very large root system at a very young age making growing them in a pot for very long without damaging them difficult.
Chokeberries also don't usually set on fruit for 3 or even 5 years when grown from seed, and sadly starting them early is unlikely to change that.
Personally I would wait until the frost is almost gone and start them in largish pots just to make sure they sprout without getting chewed on by
mice and plant them out when they are only a couple inches tall. Also be sure to stratify the seeds if necessary, or they may not all come up.
Good luck!