Pokémon League

Okay, is it just me or is the Elite Four in FireRed almost impossible with Pokémon below the level of like 65? Because the first of the Elite Four uses Ice type which I’m pretty sure is 4x effective against Charizard and at least 2x effective against Venusaur (not sure if poison type is particularly weak to Ice type) but I’ve repeatedly tried the first member of them a load of times and I’ve only beaten her once, but even trying with the same team over again, couldn’t beat her.