Wait!! :thumbsup:

It'll take a week or more to build up a significant root system (depending on the size of the cup). Personally I've noticed that when the plant has finally reached a bit of root binding (best time to transplant) it will nearly stop growing (it's still growing just REALLY SLOW). Then let it dry out, pop the cup off the dirt/root ball,.. Stick "her" into a bigger pot.

Being less then a week old, it likely has just a few tap roots, less then a few inches long too. When the plant get's transplanted it NEEDS to have enough roots,.. TAP ROOTS leading to FAN ROOTS to HOLD onto the dirt it's in now.

When I've used seed instead of cloning, I used some 2" pots (2"X2"x2"). It took around two to three weeks to root bind the tiniest bit, and each plant has around 3-4 nodes per plant.

Because this plant can grow SO fast. It's easy to see it slow down suddenly if you look at it every day. Your seed however, will start slow. When it gets it's first regular leaves, you'll see it SHOOT up from the pot. THIS is when it gets fun! Just look every day (like that will be an issue! :S2

BTW... If this cup is clear plastic... Wrap it in some Duct tape to keep the light off the soil and roots. Light reaching the soil can start algae in your soil and lead to root rot.

Good luck