My sixth form has mixed Year 12 and 13 tutor groups as well, and at the start of the year there might as well have been a forcefield between the 2 year groups because no-one mixed at all, but after the first term or so we actually started talking to each other! This time last year, I was really looking foward to starting sixth form as well because I wanted the freedom of free periods, the more relaxed relationships with teachers and the chance to study subejcts I actually enjoy in depth. It's true that some teachers still treat you like children because I guess if they've been teaching Year 7 then have a Year 13 lesson next, they find it hard to adapt, but most do treat you with more respect.