If we translate it based on english, the meaning become "saya jatuh cinta dengan cepat" But, it's better to say it "Saya mudah sekali jatuh cinta"

It depends in the context. If by 'quickly' you mean 'in an instant', you can say 'saya langsung jatuh cinta'. If you mean quickly as a habit, as in easily, you can say 'saya mudah jatuh cinta'.

"saya cepat jatuh cinta" is better :) in other words, you're easily fall in love. whoohoo! :D

Less precise answer "saya jatuh cinta dengan cepat"

Aku/saya mudah jatuh cinta :) Or saya cepat jatuh cinta