Need help in figuring out kitten sex

Our kittens are 4 and a half months old now .. I was pretty sure I had their sex figured out .. We sent our male cat to the vet to get shots, dewormed and neutered but was shocked when told that he is a she lol.. That's the cat in the right side photo ... So I'm questioning the sex of our other kitten who I figured was a female but now I'm not sure ... She is the one on the left .. I felt to see if I could feel balls but didn't ... Can I please get your opinion.. We are taking her to the vet first week of November to be spayed and get shots and all that fun stuff so they can tell me for sure then what the sex is but I want to know before then to put my mind to rest lol

They both look female to me, but i'm definitely not a professional lol 

Females have their 2 holes closer together, males have more space in between.

Males look like an upside down exclamation point ¡

Females look like a colon :

The one on the left is male. I think the one on the right is female. The picture isn't as clear though, so I'm not positive.

I think you got their genders backwards. I strongly believe the kitten in the left pic is a male. Obviously the kitten in the right is female.

Is it possible for a cat to be male without balls? I have felt all over to see if I could feel them but there's nothing to feel

Yes, it is possible. It's called undescended testicles. It is rare; but, certainly happens. There have been a few members here with such cats. Neuter is more like a spay in that the testicles are often located in the abdominal cavity area.

Both are girls.. The vet confirmed it when we took her to be spayed