I got it all through grade school. I guess it helped a little, but the only way I truly learned was through real experiences and teaching myself.
I went to a smaller middle school (300-something kids), and it was torture. I had a small group with three other people where discussed stuff (I left after a year because I wanted desperately to be normal, and I felt like the group did nothing for me).
In high school I saw a special teacher who helped me deal with mundane interactions - confronting teachers with issues, time management and how to interact with others. This was as helpful as it could be - I didn't get much from this either, but it acted as sort of a salvation from me, like a mini therapy session. She'd encourage me to talk to other students and to go to certain clubs, which I never went to (at the time, having been harassed in middle school left me with little self-esteem).
The only time I learned was later on in high school, where I paid attention to the mistakes I made and reminded myself not to make them again. College also led to a big improvement in my social abilities.
Definitely pick a larger school. If you're overwhelmed by it, there will be staff to help you out. It's just better for socializing because rumors won't bite you in the ass as much.