I have an Eevee and I want to evolve it into Leafeon. It is lvl 100 I battled like 13 times near the rock, but it's not evolving.
You cant sorry, your only options now are to evolve it into Jolteon,Flareon, or Vaporeon seeing as those are the only one that dont need level up to evolve.
You cannot. This is because it has to level up near the rock and cannot do so because it is level 100.
you cant, as it is level 100
solution:get another eevee
Well this answer is kinda ridiculous, but you could breed your eevee to get a level 1 eevee that you can evolve to a Leafeon.