Step help + camb maths entry

Hi everyone how are you guys I’m in y13 and i wanna apply to camb maths for 2027 entry so ima take a gap year. In my gap year is it okay if I enroll in a uni in my country and study maths and Econ there and that’ll kinda be how I used my gap year beofre going to Cambridge

Now about the step My school doesn’t offer fm or physics so self studying both of those, gonna do As fm in June 2026 alongside my other 3 subs and the full a level in June 2027 or November 2026 not sure but anyways I wnana start prepping for the step asap. I have around 19 months till the exam and I’ll be giving the step regardless of I I get an offer from camb or not. My plan is from now till summer is to finish all foundation modules and step 2 modules, and in the summer learn a2 fm content (pure only I already have fm stats knowledge) and finish step 3 modules by Jan - Feb And then Feb - June Js do full papers build stamina etc Any other advice or is my plan good Tyat