I think that sounds very doable. I assume you're taking geneds along with those to fill out your schedule? If not, that seems quite light. If you're not good at chem or physics, this might be difficult but otherwise, you should be fine. Most post-bacc students take o-chem/physics/calc along w/ an internship their 3rd & 4th semesters (often 2nd summer is o-chem II/physics II/upper division bio/hospital internship (cont'd) in a 15-month program).