['ive been working as a part timer at a store for 3 years, recently they offered my management position instead of a full time position , i was in shock', "Now that's a nice surprise.  You must have really impressed them.", 'ive always been a good worker, i even tell management when they are messing up and correct them , im still not sure if want management but im still very surprised']
I'd take it.  You sound like you might be good at it.
got offered assistant manager