a level combination and confused

[lyric kindle]

i have no idea what country im going to study in
i think ill be doing petroleum engineering again not sure but idk if petroleum engineering is a degree or do you do engineering then specialize in petroleum later
then should i do physics and maths a level or do physics a level ,maths as and chem/computer science as

[timid stirrup]

Maths as+al
Chem as+al
Physics as+al
Computer science as/al

Also after alevels, you need to do a "Bachelors in Petroleum Engineering"

Or anything similar like "Bachelors in Chemical Engineering"