I'm thinking of catfishing a girl that I'm interested in
I hope you are joking. Why would you do something like this?
I'll do it again if I get the chance, but next time I'll check whether the girl I want to catfish is even online
If you are interested in this girl and she becomes interested in you then you should not catfish. She will eventually want to meet you and you will have to tell her the truth.
Good point. I'm going to think about it for a bit.
I'm glad that you are going to try and think about this first. If you want a real connection with someone it is expected to be honest about yourself. Lying will only cause more harm and heartbreak.