What level does bagon evolve if you dont let him evolve at the first time?

If you don't let Bagon evolve the first time, then every time it levels up it will start evolving again. Then if you don't let it evolve again then the next time it gains a level then it will evolve again. It will keep evolving as it gains levels inless You give it an everstone. Hope that helped :)

~Gracygoo