Yes, I was 18 in the Easter holidays of my first year. I don't think there were any particularly negative effects. I'd moved up a school year when I was 5 so I was used to being the youngest. The only thing I remember being cross about was that there was a general election a week before my 18th birthday and literally everyone else was voting for the first time and excited about it, and I couldn't. I did drink illegally in college bars for 2 terms because it would never have occurred to anyone to ask for ID there.