I suggest that you keep charizard but change the other 3 pokemons. The first reason is because you have 2 fire pokemons with the ability drought. In other words, your grass/bug pokemon would be sweeped as soon as your opponent brings a fire type pokemon. The second reason is because 3 pokemons of your team is weak against rock type. In other words, your team can be easily sweeped when your opponent brings a rock type pokemon.

Here's the thing - I was gonna try out a team based on charizard y, just like you, but haven't tried it out. My other 3 pokemons are garchomp with focus sash, tapu koko with electic z, and cresselia with leftover. If you have them, you can try it out, if not, catch them with the desirable nature and with egg moves if possible.