Plants 3 weeks old, to close together what should i do?

SO i planted some pot outside about 3 weeks about their all about 4 or 5 inches tall. 2 of them are about 3 inches from each other the other is 4 inches away from those. do i need to transplant all of them? Another thing, ive noticed when i water them they fall over is tht bad? Do i need to string them up to a stick or something?
Thx.

Well, unless you intend to grow all 3 in the same pot, you will need to transplant a couple of them at some point...

Might not be a bad idea to gently support them with sticks

What Chuck Darwin would say.

Kill the weak ones.