nursing?

I got offered my first choice which is Diploma in Nursing at Nanyang Polytechnic, Singapore.
Should I go? Really can't make up my mind la...

Aunties and uncles are not in favour of me studying in a polytechnic because they're afraid I might not enter university.
I really appreciate them and their support, wanting me to get into university.

So, what's next?
Diploma or STPM? If STPM, Physics or Biology?

I feel helpless and useless especially when it is so difficult to make a decision.