Happy 16th-To my child

I decided to write you a poem,my dear,
To honor your 16th year...
I sat and I mused,
It must be just right
To make my thoughts perfectly clear...
Though I've known you only
A short little while,
You've become like a daughter to me...
And I'm so very proud
That you feel the same way
So 'Mamma Jan' I ever shall be...
Yes, I racked my brain
For the perfect words,
But I just don't know how to begin it...
For you see,though you didn't grow under my heart,
Little one,you have surely grown in it.