@CactGuy 
to the Adenium forum! That is pretty amazing for a 3 weeks old.
That is hard to know at this time but if you did it just one time it should be fine. From what I read, some Adenium growers would give their seedlings the first taste of fertilizer after 1 month. Then other growers would give their seedlings a diluted balanced fertilizer every 2 weeks to speed up the flowering time. Their goal is to give their seedlings a faster chance of growing and seeing the bloom sooner.
Keep us posted though with your progress, that is probably exciting to see them grow fast! I have several seedlings but they are quite small for even over a year old. I have just given some their first taste of blooming fertilizer.
