Don't worry about the lack of teeth; gums with teeth below the surface are really hard and can manage to chew a lot of things.
She'll "learn" to chew through practice so just offer things that require chewing. Maybe the pasta stars caused gagging because she thought it was her usual smooth puree and wasn't expecting to suddenly find lumpy bits. Maybe try finger food like steamed veg, toast finger etc as it will clearly be different from her smooth puree.
Gagging is the protective mechanism. It's good to gag. I went on a first aid course before giving food to alleviate worry of choking. I do BLW so mine has been eating finger food type stuff from 6 months. Gagging in any significant amounts only lasted a couple of meals.
My DD is approaching 7 months and has been on solids from4 months. Slowly I've been making the foods thicker but my LO has no teeth & does not want to chew! She's even gagged up loads of the baby pasta stars, to my horror as I panick when I see her struggling (I vision choking ) i am really keen to get her eating boiled veg & finger foods but how to you start? I'm really scared...