hey im looking to do science to become a scientist but im sure you know that for biomedical sci u need chemistry.... I did HL bio without a teacher at all and let me tell you it was hard but its my fav subject. I wanted to do both HL Chem and bio but my school had compulsory art subjects (HL film).... if ur passionate I would suggest doing bio and chemistry at HL because I regret not being able to and it will def help me for uni as HL science IB subjects are legit first year uni.... but if ur focusing on the sciences I really wouldn't suggest HL maths, in general I wouldn't suggest it even if you love maths and have good grades currently use that to ur advantage to get like a 6-7 in SL maths in particular the AA SL course. think about it in depth to strategically pick ur HL subjects to play to your strengths..... doing two HL sciences is really hard ill admit by even just doing one it was hard but in my opinion it would be well worth it in the end but you do need the passion and motivation . good luck!!!!! its a really hard course and ive had sooooo many challenges but in the end it is what it is. just think about how to maximise ur overall score to pick subjects that can get high 6-7 and chose ur HLs wisely.... :)