will i get into sixth form

The requirements for studying A Levels honestly depends on the college or school you're applying for. However, I would say consider going straight from BTEC to University, as more Unis take BTEC than you'd think these days (if you want to, but i'm assuming you want to study A Levels to go uni).

yes i want to do a levels cos that’s what i originally wanted to do and i hate btecs,

Hmm so I'm guessing you wouldn't finish enough of a BTEC this year to get into Uni? Do you want to go to uni?
I'd have a look at your college's options, or other colleges and see if they offer A levels, they should explain their requirements there. Schools are a bit more difficult as if you go to college you usually don't go back into school but you can have a look at local school's websites and their requirements. Would you rather go to college or school? Are there many options for this near you?

it’s a lvl 2 diploma so i’ll get the qualification and i’m 16 atm so doing a levels isn’t a massive effect. i’ve got a lot of colleges i can go to. i’ve had an interview and they said i should get an offer and i’ve got another interview next week with another place. i’m just anxious if it’s enough

A Levels are Level 3 Qualifications, so the natural next step up from Level 2 Qualifications. You should be fine