is it paid?

Seems odd to be taking a temporary position as a recent graduate. Why not just seek full time employment? Being a recent graduate should be enough to qualify for a junior position.

take 6 but build into your offer a performance review around month 4, with the option to extend to 12.  that way if you hate it, you're out, but if things go well, you can extend

You should also make clear your intentions during the interview process. You've finished your M.arch, so youre really more of a junior designer than an intern. Let them know that you're eager for this opportunity, but you also see yourself staying at the firm longer-term than just an internship and that you want the opportunity to transition into a proper JD role moving forward after the initial internship period.

With an M.Arch under your belt you really shouldn't intern more than 6 months, you'll devalue yourself and your education. If they are not willing to offer you a position after half a year they're not going to offer you a position after a year either, they'll simply replace you. You also don't want to work for people that don't value you or your work and treat you as an intern for an entire year, just so they can save on paying a decent salary.

You would only just be getting "your feet wet" after 6 months.  You really need a decent length of time to learn anything and absorb the office workings.  12 months is a min in my opinion.

There are a few firms I know of with that formal 6 or 12 month internship structure - the ones I'm familiar with tend to treat their internship programs as a separate channel from long-term hiring, and view the interns as people who are there as a transitional step, to get resume material, a prestigious firm's name, and some familiarity with basic office norms, before they move on to their longer-term "real" career elsewhere.  In other words few if any of their interns are offered permanent positions within those firms - it's more of a use 'em up and burn 'em out deal - a way for the firm to have a never-ending supply of new grads with the latest software and presentation skills, with eager-beaver attitudes and energy levels. There's not really any expectation of upward mobility in that role, as they'd rather keep the steady rotation of fresh grads.  Since I don't know which firm you're considering I can't say that's definitely the case there, but if I were you I'd try to talk with some former interns from that specific firm to get a sense of whether a longer-term role is a realistic consideration or not, before I'd try to make decisions based on qualifying for a position that might never exist.