Agave's like to be pot bound so it is probably fine. Only way to be sure is to knock it out and look at the root ball, but it doesn't look crowded to me.

You’ll know it’s crowded when the pot cracks!

It's an AGAVE and it's in your CASA, how big do you want it to get?! Some species are HUGE. I think the pot is fine. I love Agaves.

I guess as big as it can, not sure how big it can get by being kept inside.