Theres no way of telling with that much information. What about beam bars and vault? And all the basic elements on floor? Full Twists are hard but I'm sorry theirs no way of answering this. Good Luck.
You can't so just floor you need bars beam and vault as well. And also for floor just having a full twist doesn't even mean anything you needa be able to do front tumbling and back tumbling an turns and split leaps and all sorts of stuff
Based on just the full twist, I would say level 7/8. But it also depends on your form. Are you setting? are your legs together? How much height are you getting? Are your legs tucked or do you lay it out? (It's fine to tuck a full but laying it out is more of a higher level skill)
It also depends on what you can do on the other apparatuses (bars beam and vault) but probably around level 7/8
