I do think it's normal to all of a sudden freak out at how quickly time is going by and the sadness that you're missing the little things because they get lumped in with all the mundane shit.
It's hard to realise that time is passing especially if, like me, you never really imagined anything beyond the "I'm having a baby" years. I could always visualise my exciting life up until that point (travel round the world, get a career, meet someone, get married, have kids) but had no picture of what my life would be after those babies were born and growing up.
This is where I think of a lot of women struggle to identify where they stand in life especially if they have devoted a large portion of their adult life to raising their babies (nothing wrong at all with staying home, I just use this to illustrate my point) I was lucky that prior to having my babies, I fell into a very good career that interests me (surprisingly as it's dull as fuck to most people) and I have goals over the next few years that are only for me. This brings the focus back to my life and what I want and makes me concentrate on the here and now, not daydream wistfully about the years gone by (which I find I'm doing but only because my ass is now flat as a pancake whereas it was fabulous pre-kids).
I have found that by bringing the focus of my attention back to myself has helped me avoid that panic that my kids are growing up. Because they're supposed to grow up and become independent (only 3.7 and 15 months so a way off yet!) but it's not too soon to develop your own interests and life that mean instead of thinking "my babies no longer need me" you think "my kids are growing into wonderfully independent people and here I am with these most brilliant adventures planned ahead."
Excitement and adventure aren't just a young person's pursuit... 