What is it about 2 1/2?

What is it about 2 1/2 that makes me cry for all the time that is already lost to me? When each of these kids turn 2 1/2 I have a sudden panic attack... oh no! he/she's 2 1/2 already! Where did the time go? Have I done my best? Have I completely ruined them? How did they get so big already? I can't even remember now exactly what the statement was but something to the effect of, kids are done at 3. You've had your opportunity to lay a good foundation for the future. If you didn't, well then good luck on the next 15 years. I panic because already 2 1/2 years are gone and I can't remember what I've done. Did I lay a good foundation? Is there enough time left to fix all my mistakes? I think my panic is also related to the fact that at about 2 1/2 they usually have a big leap forward and just start acting like a big kid. Good-bye Baby. Even though Felisa has thought of herself as being at least 10 years old for the last year, she has had a big jump developmentally in the last month or so. Sad, scary, hopeful...