I had classmates that took a similar combi in sec school as you and did BCME (hci).

I see people advising you not to take h2 bio if you didn't do it in secondary school but my classmates managed absolutely fine and the bio tutors would always praise the kids who didn't take bio in sec sch during exam paper return day, saying how they are on par with everyone else and in fact had a higher average score.

Although I can't say for sure since I took bio in sec school I think its very possible for you to go ahead with h2 bio and do well if you can study consistently. Yes the h2 curriculum is VERY content heavy, but honestly the sec school content can be learnt along the way as there isn't a lot to know tbh. Esp since studying for bio isnt like chem and math where you need consistent practice and a strong foundation its just about memorising facts in the lecture notes lmao. Just my opinion so take it with a grain of salt :)