Posture and (Hypoextended)? Legs

[FionaL]

I had a pointe class the other day and the majority of it was focusing on our posture so that we have it correct for harder pointe work. This was just standing facing the barre in first. My teacher said a lot about “wrapping” the legs around so that the thighs and knees are touching and so that our bums aren’t poking out. However, my legs are quite straight and not at all hyperextended, so it’s difficult for me to get my knees let alone thighs touching while trying to wrap my legs around and under. If I wrap them around and under as much as I can, it’s impossible for any part of the inside of my legs to touch. I can only get my knees to touch if my pelvis is tilted back slightly and even this is quite hard as requires a lot of effort and I’m always really sore afterwards. When my knees are together my right foot always rolls forward. I’m wondering whether this is all due to a lack of strength in the right places, and what I could do to fix it. My turnout also isn’t the best so that also might be a problem.

Any advice is appreciated, thanks!