How much will a full grain belt stretch, and how long does it take?

I just bought a full grain leather belt a few weeks ago and finally got it in the mail. It fits, but unfortunately it looks like I underestimated my size as I can only squeeze into the second to last hole.

I know that leather stretches, but I read that full grain is more resistant to stretching. If I wear it every day, can I expect to move to the next hole at some point or will the stretching be very minimal? If it will in fact stretch significantly, is that a process that takes a few months or is it more like years?