when i was in elementary school i was always getting A's on all of my homework
That's great. Good scores on homework early on can really set someone up for success.
yeah but it was weird beacuse after elementary i was not doing that good in schooll
Homework can improve academic success among older students. However, its effectiveness is also often debated.
that is interesting and good to know, do you know much about elementary schools?
A little bit, I grade elementary standardized tests. Those tests can really create undue stress. 
i was not aware of that it is good to know since my little boy is about to start elementary school
Yes, stanndardized tests show achievement gaps, grade points, drop out rates and college enrollment also show the gap.. These things can be helpful in terms of showing who needs most help.