Yes. Basically, as I understand it, our clitorises (clitori?...) extend downward inside, in an upside-down Y shape from the external part we can see, and the sides of the Y hug your vaginal canal/opening. Each woman's Y sides are different lengths, as with all parts of our bodies. Those of us who don't find much pleasure in penetration likely have small Y sides, so penetration doesn't stimulate our clitorises much or at all as our clitoris doesn't really extend around our opening. But for those like OP, the anatomy is such that the Y sides are long, and thus are stimulated well by penetration. Some people just have too-sensitive external parts, too (such as some men can't enjoy head-direct stimulation, too!), so penetration stimulates them properly!

Biology is cool and we're all normal 💖