I'm 43 and had my last baby at 40yo and he's still nursing. I considered myself perimenopausal when I got pg.
I'm not completely sure I understand your question. Perimenopause/Menopause is a spectrum, and the hormone shifts seem to work in jags. My periods lengthened out, but since have returned to a steadier cycle. All while nursing. But as mentioned, I thought I was well on the spectrum before even getting pg and nursing for the past couple years.
So if its a yes/no perimenopause while nursing, I'd say "yes."