[have resigned] or [am resigning]

[ansonman]

I have made up the sentences below.

(1a) (Suppose that my last day of work is three weeks from now. I submitted my resignation letter yesterday.) My coworkers asked me, "We are going to start on a big project in a few days. Are you excited about it?" I answered, "I won't be doing it with you because I am resigning."

(1b) (Suppose that my last day of work is three weeks from now. I submitted my resignation letter yesterday.) My coworkers asked me, "We are going to start on a big project in a few days. Are you excited about it?" I answered, "I won't be doing it with you because I have resigned."

Some of my non-native friends think "have resigned" is correct because you have submitted your resignation letter. My other friends think it's okay to say "am resigning" because you need to continue with your duties until your last day.

I am not sure who is correct. Please help me. Thank you very much.

[Alan]

Yes, 'have resigned' is appropriate.