I'm glad your PT is not pushing it, but what's his rush? Don't let his goal become yours, or you could start to get anxious.I am hitting 90 degrees now, so my next goal is 120. He said the hope is to hit 120 in three weeks, but we are not pushing it. He said it will happen when my knee is ready and not before, and if we try and force it, it will only delay it. (I think some of y'all on here should be PTs too, haha)
You have a whole year after surgery to achieve a ROM of about 120. There's no time frame in which you have to get there, no "window of opportunity".
Myth busting: the "window of opportunity" in TKR
My own ROM continued to increase spontaneously for about 15 months.
As the others said, don't do the squats. your knee isn't ready for them yet. You already do a version of squats every time you sit down or get up off a chair - and that is all the squats you need to do right now.My knee is swollen and stiff again today. We did squats for the first time in PT yesterday, and although it was ok then, my knee is telling me I am not ready yet. I'm laying in bed now with my leg up, icing, and wondering if I should take a nap.
New Zealand

I'm a little over 3 months and mine is at 115/0 and I'm still working on it.