I was playing a game with my little sister; still a beginner at chess. I showed her the Queen's Gambit, and she said she prefered moving c3.

I had never seen this opening played, and I couldn't find it online. What is it called, and is it sound?

It's called D00 - Queen Pawn Game , wheter it's a sound or a not, I can't a say, I've never played it or against a it, yo!

please never use that chess set ever again.

There is an opening called kings head, which is 1.e4, e5, f3, instead of f4 for the kings gambit. This is the same but on the Queen's side. And it is sound my step dad played it against me.

No particular name (as Gab has said - Queen Pawn Game or Queen Pawn Opening).

There is only a handful og games in database. It is not bad or unsound.

1.d4 d5 2.c3 Nf6

  3.Bg5 e6 4.Nd2 Be7 5.e3 0-0 6.Bd3 Nbd7 7.f4 c5 8.Nf3 b6. 9.0-0

  3.Bf4 Bf5 4.e3 e6 5.Nf3 Bd6 6.Bg3 0-0 7.Nbd2 c5 8.Be2 Nc6 9.0-0

Seems weird to me. That pawn isn't doing anything constructive on c3, other than blocking the b1 knight from a good square. On the other hand, it does let the queen out, as in the queen's gambit.

If black plays c5 early, you could end up transposing to a slav with colors reversed, which should work well for white, since he'd be up a tempo.

Another option is that White might be going for the Colle System, when c3 is a standard move to play eventually, just getting there via a weird move order.

Personally, I wouldn't play this. If you're going to play d4 without c4, go with an established opening like the Colle, Veresov, London, etc.

--Fromper

It is a common move in some queen pawn systems like the Colle, London or Torre or even Trompowsky. So it's not that bad.

But naturally 2. Nf3 and 2. c4 are the moves you want to play if you want to get something of an advantage out of the opening.