What comes after 29?

So this is an actual conversation that took place betwixt myself and my clearly very tired daughter (She is in bed. Her lights are out):

Lucy: What comes after 29?

(Now here, just let me insert that my child asks me questions to which there are often no right answers. We can go round and round all day long and I can never give a right answer. So when she asked this question, you see, I was very excited. Finally a question that has a concrete answer! I can't go wrong!
Or can I?

Lucy: What comes after 30?
Me: 30!
Lucy: No! I already counted 30.  What comes after 29?!
Me: Ummm.... 30?
Lucy: No! No! I already counted 30!
Me: Lucy, honey.  I don't know what to tell you.  30 comes after 29.
Lucy: It didn't yesterday!!
Me: It didn't?
Lucy: (silent head shake) I already counted 30.  So..what comes after 29?

(Holy balls.)

Me: Sweetheart.  30 comes after 29. Look. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30.  See?
Lucy: I already counted 30!
Me: Okay, well 31 32 33---
Lucy: NO! I already counted 30. I already counted 40!
Me: Well, why don't you start from 50?
Lucy: I counted 50, then I counted 60! What comes after 29?!!  (completely crying by this point. I am trying not to laugh.)
Me: Maybe I should go ask Daddy. He's good at math.

(I go downstairs just trying to buy some time. Actually I'm hoping she'll just fall asleep. Tad's in the bathroom and unavailable to tell me what else might, aside from 30, come after 29.  I go back upstairs.)

Me: Hi honey. I talked to Daddy. He said that 30 comes after 29.
Lucy: (Frustrated) Look!  1 2 3 4 5 6 7 8 9  10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30.  Yesterday I didn't count 30!
Me: Well, could you start from 30?
Lucy: I already DID!  1 2 3 4 5 6 7 8 9  10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32.... (I am trying to suppress a smile.  Obviously I brought this on myself by counting in the first place. Meanwhile, she is still counting very angrily and loudly)....45 46 47 48 49 50! (then she cries)
Me: Oh, honey, it's okay. Sometimes you get lost in counting.
Lucy: No you DON'T!!
Me:  Sweetie.  I think maybe we should stop talking about this.  Do you still want Daddy to come check on you?
Lucy: I want you to!
Me: Okay, I'll be happy to.  I'll come check on you in five minutes.
Lucy: Okay.  What do you count to for five minutes?

Oh boy.