Buying a department store bike AND then going to an LBS for adjustment is a terrible idea. What, you spend 50% of the purchase price just to adjust it and not even get better components?
And going to an LBs with a department store bike is a recipe for condescending comments and guilt trips.
But adjusting a bike is not that hard to learn. If you are mechanically inclined at all, you should be able to adjust a department store bike.
If you are not up to that, buy the bike from a good LBS.