"Heroin is not necessarily addictive and harmless if used correctly."
True. It's used as a painkiller. I had it just prior to an operation. Did me no harm at all.
I'm grateful I had one or two teachers who were open, honest and objective about drugs.
Never had their own gear though. Always bloody smoked mine. Mind, fair trade I spose for letting me sit in their office at break, and skin up.
Concentrate on the important things at university: beer and birds.
Sage advice. It's very very unlikely you will get the same 'opportunities' ever again. Enjoy it while you can.
And don't worry about a 'career' ffs; there won't be any jobs when you come out of Uni anyway.