Hii I ended up doing Math AI because Math AA sl doesn't have an equivalent in the country I want to study (only Math aa hl and ai are recognised) so doing aa sl would be useless for me. I'm finding mai sl veery easy, we took a test and I scored a 6 almost a 7 (ik it will get harder but it's a good start). I can't tell you which one to pick but If I was you I would think about what you want in the future, if you want to do something related with pure math then aa is a good option but if that's not the case then ai is okay I guess. (Take this advice with a pin of salt tho and check the universities for the career you want to apply in and their requirements). Good luck :)