It is really just the "are too strong for you" I am having trouble with. We haven't gone over how to say stuff like that in class yet. Would you use the superlative?
I noticed that nobody has answered this yet, so I decided to make an attempt myself (despite also being a student). Apologies for any mistakes, this is my first time answering a question on here.
I am not aware of any way to specifically say "are too strong", but I think the sentence below has a similar sense using nimium. I also used potentiae rather than something like virtutes in an attempt to make it sound more forceful.
meus potiones nimium potentiae tibi habent - My potions have too much strength for you
Alternatively, you may be able to use phrases like "my potions will overpower you" or aliquantae (considerable [amount]) to express the level of strength in a different way.