I am 43 got tubes tied in 1995 after my daughter was born. For last 3 yrs my periods have been wacky. But for a few months now they have been every 19 to 21 days I missed a month and then had one. I ended last one July 16th was suppose to start the 8th of aug and so far nothing.. Is this part of perimenopause

It could very well be. The machinery could be shutting down. Maybe at your next doctor's appointment you should mention this and they can do a hormone screen and see if things are slowing down.