I feel like an idiot...

So. Am I supposed to start breastfeeding with the breast i fed off last? Does it matter how long i fed on it for?

I feel like this seems obvious and like stupid questions.

My daughter is 4 weeks old and she seems to only feed off me for 6-10 minutes and then pass out. I burp her and then wait to see if she starts rooting. If she doesn't i lay her down and anywhere from 5-30 minutes she starts to root and get fussy.

So start feed on the same breast or my other one?