history: My youngest child started high school this year. It made me think back to when she was just started kindergarten, and how time flies! My youngest child started high school this year. It really made me think back to her starting kindergarten_comma_ and how time really goes by. I can just see her learning to read!
current: It is so hard and so rewarding to see them grow up. 
next: Yes, it really is bittersweet. But, the older they get, the easier it is to think back to the younger days!