How hard is it to upgrade from Nikon D40 to Nikon D3100?

I have had my Nikon D40 since 2006, i love it, but it is time for an upgrade.

i really like what i have read about the Nikon D3100, i would keep my D40 but i have had some people from school ask me about selling it to them.

i was going to sell my D40, (I'm 15 so an extra couple hundred dollars will go a long ways) then buy the D3100. But my sister told me that she heard it was really hard to figure out the D3100, and that i should not sell it at least until after i get the D3100 (that way if i get a job, or i need to use a camera i can go to my D40 so i can use a camera i know all of the buttons to.)

what's your opinion? (sell my D40 before or after i buy the D3100)

All of Nikon's entry level cameras… All their cameras for that matter pretty much have the same layout.

I, too, have the Nikon D40. I picked up my friends D3 and started shooting right off the bat. Just go check it out for yourself, I don't see anything being difficult.

If you can figure out the D40, you shouldn't have a problem with the D3100.

I won't sell a fine D40 then add 200~300 bucks to buy a D3100. Instead, I will use that additional bucks to buy new lens.

If I will upgrade a D40, it will be at least a D7000.

I'm sure if you have mastered D40, you can operate any Nikon DSLR.

You can sell it before your sister obviously knows nothing about photography or is very far from an intelligent person, there's really nothing to figure out its pretty much the same almost other than the fact that there's a guide mode included on it and video recording.