first time at it legitlly

I've grown before, I'm 19 and my parents were okay with it as long as my dad got half or what came out. I planted five, just to see and i got two. It was very guerrilla IMO, since i just thru them in pots and let them take the light from the backyard light at night when the sun wasn't out.

Long story short, I was lucky enough that those two plants were female, had to bring them indoors in our shed with little light, they yeild enough to smoke for a few days after curing, I was proud but i knew i could do better and knowing that i apparently got this magic touch lol (2/2 females) i wanted to do a few plants in the same shed however, with lights and such since money isn't so tight this time around.

I've search around here and other forums, and the information i found seem to be for massive grows 10 plants or so. I was looking on a much smaller scale such as 5. I'd be happy if i get four females.

Is it wise to have a small amount or should I plant more?

What type of lights should i be looking for?

Are there any type of different rules with fewer plants that i should know?

Seeds: I have some, nothing great but i figured if all went to hell i wouldn't be as mad as i would be if i spent top dollard on seeds, should and can (live in america) i buy off online? if so where would be most trusted?

Anything in general that should i be aware of or know before i start?