Your mom is getting married soon, but you've only known her future husband for
two weeks...?That sounds a little strange to me
(Did your Mom explain to you why she's only introduced you now, not long before the wedding?)
As for your future step father, I suppose it really depends on exactly what he's telling you to do...
Is he asking you to do stuff like, help clear up the table after a meal? Is he asking you to put your coat away instead of leaving it on the floor? Is he asking you to get your homework done?
Are any of the things he's telling you to do "unreasonable"...?
Or is it just because you don't know him well enough yet?
No one likes being told what to do of course, and it's difficult when you first get to know someone to listen to them telling you what to do... but if he is going to marry your mom and share her life
and your life every day, it is probably a good idea to get to know him a little better.
If he's telling you to do bad or inappropriate things, then you should ask your Mom something like: " (His name) told me to do (whatever he said you should do)... is that ok with you, do you want me to do it too?"
That way, it will not seem like you are totally against him but instead asking your Mom for guidance on what's the right thing to do.