First Time Grow From Bagseed! Please Help

Hello I Have An unknoun Strain plant,i have it under 12/12 light since seedling it is now only 3 in. its about 11/2 weeks old.i will be posting pictures soon.just need help with the grow cause I honestly don't know what im doing. I started plants in miracle grow. i was wondering when will i know when my plant is about to show its sex.im not sure what t is but were the stem from leaves actually comes out of the stoke has a little thing growing out of it.i know its not a pollen sack or anything but i was trying to figure out what they are.theres a lot of them and seem to be coming in pairs.only reason i started seedling 12/12 light was to determine the sex so im not wasting my time growing a plant.like i said its just i a seed i got aout of some dirt weed.another thing since the seed came from dirt weed will that mean that's what ill get?all forms say it depends on how yu grow it.bti wana know if it could possiably grow weed like kush or dank etc?