Put them outside in full sun early in the day shaded after 11 am, evening sun after 6 pm until dark.
Window sills are not good.
I'd repot as soon as you can. It's that time of year. Things are starting to grow.
5 gallon pot minimum
mix 1/2 cup of bone meal into potting soil before transplanting
Water in with a high middle number fertilizer / flowering mix like 5-15-5. This gets the roots growing.
Put them back outside in full sun early in the day. Shaded after 11 am, evening sun 6 pm until dark.
Water with the low nitrogen high middle number flowering mix again in 7 days.
If the plants require water mid week just a little plane water.
In 14 days.
Switch to a high first number lower middle number veg fertilizer like 12-6-6.
1/2 strength for 2 or 3 weeks. Anything you can get your hands on will do and place the pots in full sun all day.
After 2 or 3 weeks on higher nitrogen fertilizer you can mix 3/4 strength as directed on the bottle.
Your little seedlings will be pretty big buy this time and growing fast.
Watch for signs of bud formation late July. When your sure she as finished growing and stretching. Switch back to the flowering mix high middle number for the rest of the grow.
Be careful not to over water. Let the top 2 inches of the soil dry out before re watering.
If you have a little
Cal-Mag 1/2 tsp pr gallon of water once a week start to finish will help.
Do this and you won't believe your plants in 60 days.
All the best. Ron