I have grown a large number of unusual citrus varieties but don't recall ever seeing wavy margins like these. In fact at first I thought these are not citrus at all, but looking at the petiole end, and imagining the leaf flattened out, I've changed my mind. Perhaps the wavy edges are the result of some unusual growing conditions or your fertliser program.
From the petiole size and the leaf shape, I'd guess they are a mandarin or clementine, or hybrid of them. How old and tall is the plant? It will be interesting to hear eventually what the fruit is like!
The citrus ID tool link given can be useful, but you need to look at particular named cultivars.

Here is a link that might be useful: Citrus id tools

I know you don't have many leaves; but if you can crush one of the older leaves and smell it; it will greatly narrow the possibilities. Orange smells sweet; mandarins as well; lemons are definitely lemon/lime; and grapefruit/pomelo smell like themselves.
It is also possible; because you planted a seed, that you could have an entirely new variety.

This picture and link made it's way to the Citrus Grower's forum at http://citrus.forumup.org/viewtopic.php?p=65220#65220, and one of the members identified it as a Russel river lime. C. inodorata.

It does look a bit like C.inodora, but my seedlings don't have the crinkly edges. The proof of this variety is whether there are dual spines at each leaf node - it is the only citrus species to have this twin thorn characteristic.
The Russel River Lime is so unusual that you would surely remember receiving seeds - they would only have originated in Australia or in one of the major citrus collections like the one at Riverside, California. You certainly wouldn't have found this variety at a local fruit shop!