I read that the method for sexing these is quite similar to sexing leopard geckos (which I have done). But, Im really not sure about this one...
it looks like I might be seeing a very thin line of visible pores just above that bulgy skin flap, which typically indicate a male. Also, that bulgy skin flap seems to be just a bit "pronounced", soooo, it could be a male?
However, all in all it looks pretty flat too..
So, Id really suggest trying to find someone you can show your gecko to in person who has some experience with them, that person might be able to determine its sex within moments.
Hopefully someone can post something more definite on here for you too! lol. Sorry if Ive just confused you more!!