does anyone know how long it takes for your stitches to dissolve after a vaginal birth

Depends. I still had a couple left at my six week checkup.

How many did you get? @breloya

But I think the usual timeframe is 2-3 weeks. And I don't know how many I got exactly. I had internal and external stitching.

It really depends on how well and fast your body heals... Mine were gone 2wks PP and was completely healed by 4wks. I was stitched inside and out on all four sides.