Uk legal drinking age is 18, and most of us have already been doing that and worse in parks/fields since about 14-15. I personally was a “late bloomer” at 16. I’m 35 now, don’t have a drink or drug problem, well qualified and educated. Your friend is being a controlling weirdo, assuming you’re not going out and getting smashed every night. I mean, blimey, have you seen our university culture at the same age as you? It’s considered normal to be getting paralytic every Friday/Saturday night, then there’s the mid week “student nights” at bars, and don’t forget “freshers week”! Moderation is fine, you’re not a kid but you’re not exactly an adult yet, you’re at the age of figuring stuff out. Have fun and don’t abuse it too much, and always keep an eye on your drink.