few in game questions

Hey all, tried doing a search and asking in game but cant come across anything conclusive, and sorry if the answers are out there but there are so many login threads..
1) is it possible and where would I go if Id like to switch my grand company, she mentions it in her dialogue but im currently lvl 28 and cant seem to find out how?
Ive heard yes and no, or you can do it lvl 25 or you can pay etc, just wanna switch before I accumulate too many seals.
2) are all the storylines the same? or because I selected Gridania as my GC did that in turn select my main story after I picked from the 3 in vesper bay? like how the next quest after sent me back to the forest to deal with the slyphs?

To answer Q2. The main story is the same for everyone, only time it really changes is when you hit lvl30 and choose your sub. Class. So doing the different class quests, depending on what you wana build change up..

I have a question too, how I get past the character selection screen?

Send a help ticket to SE, :-P and hope they fix the issue this week :-)