I'd ask her out. Don't play those mind games with yourself either about the weight. If you were that fat and soft or unattractive, she wouldn't have slept in the same bed as you and see your last pro point (no resistance/no discomfort). From the way I'm seeing it, she's ultra passive and what most would call "decent" or "conservative". She's waiting for your first move and you've got nothing to lose. If it's a genuine friendship, it'll bounce back from any bloopers. Just go for it.