Replying an Email

Dear Sasa,

Hi! I'm great :)
Then, how about you?
Wow! It will be a great day for you.
Absolutely! I will attend it. But may be I will come late because there is something that I must to do on the day of yours. I'm sorry :(
White casual for the dresscode? Hm, nice.
Thank you for inviting me, Sasa.

Regards,

Mr. Agus