"Entrance Requirements
The likely minimum grades currently required are:
SQA Highers: AABB including at least 2, and preferably 3,
from Biology, Chemistry, Mathematics and Physics
GCE A-Levels: AAB including 2
from Biology, Chemistry, Mathematics and Physics
International Baccalaureate: 35 Points
Preference will be given to candidates offering strong science qualifications."
But depending on exactly what your offer is, there is some room to wiggle. Unless it states that you need As in certain subjects, then all you need to do is just achieve the grades. But if the course is particularly popular this year, there is always a tiny risk that they have to turn you down. But I doubt it.
[And about the 2nd year entry, look further down...]
It's not really. The degrees are all modular, and modules last a semester (which is half the year, so similar to a term). At most of the English universities you would only be taking a couple exams in winter with the others in June. But St Andrews runs the exams once you've run the course. Which personally I prefer.
You've both asked about 2nd year entry... so here goes...
Pros: You can make your degree shorter, and so save one years worth of finance. From what I've seen of the maths and physics 1st year, you're very likely to have already covered it in Advanced Highers/A levels. It presents a challenging experience, but a good one. Ummm.... that's about it.
Cons: You can't take it as easy as your 1st year counterparts, your course marks, though I don't
think count to your overall degree, do need to be good so that you can pass into honours the next year. Which puts on some stress with the exams. And you sometimes feel that everyone in the whole lecture theatre understands what is going on, and you don't, just because a lot of them are 2nd years. But it's not true, their probably just as confused as you are.
The thing about social-ness.... You still make tons of friends anyway. Both through your halls, societies and in lectures. So it doesn't matter if your in 2nd year or 1st, you'll still meet people. And you won't be the only ones doing 2nd entry, a lot of people do it. And in physics is was encouraged that if you had A-levels at least, you ought to do 2nd year entry.
What you've got to remember, is that you're new to the town, university, everything. So whichever you choose will be new and different.