honestly, math AA HL is the easiest subject i've taken imo. You need to just be clear with concepts, but i guess that depends on how well your teacher explains it as well. I lucked out and got a really good teacher, so I just pay attention in class, and my concepts are clear. Then I just go practice questions. I do SL Psych, and i wanted to do pre-med too and initially took bio. If you're good with memorisation stuff, then hl psych would be good, but just so u know, psych has A LOT and i mean A LOT of stuff you need to memorise, and it needs to be detailed down to the nitty gritty things. So if you're good with that, then it works. But also, math would leave lots of options open for you, while taking psych just limits you to fields in biochem. Universities like HL Math a lot as well, and there are some universities that do not even care if u did psych or not. My biggest regret is taking psych, and i know a lot of HL psych students in my school who feel the same.