"Hey Littlefoot, wanna come play with--Oh. I see you're playing by yourself. I'm just gonna leave you alone for now."
or she just wanted to make surprise and show up in front of Littlefoot, but she noticed that... he is talking to his water reflection, than talking to imaginary friend...
That's why she was in LBT9, but never showed up.
Now I understand why she befriended Rhett!