some schools require to get your official GMAT score before processing ur profile, while others just need the official score to verify it. Some schools say you have to take the exam before a certain deadline. But I feel that schools are not very strict about that. So I think applying this year is still do-able. I would suggest u to check with the specific schools.
Interviews depend on the schools. some are by invitation only, in that case, you don't need to worry about it. Some don't require GMAT score before the interview, in this case, you don't need to worry either.