When I had my first child, I couldn't imagine that any other child could ever be loved as much as I loved him. He was perfect and he was mine.
Writing Mara, first book baby, the gestation period lasted over 1.5 years. It was hard work, with lots of back tracking, rewriting, and having NO CLUE what I was doing. I loved my book with a fierceness to rival any Mama Bear, overlooking any and all flaws.
Then I started reading about favorite writers and following author stories. All these great writers didn't publish their first books. (Kiersten White, Natalie Whipple, Beth Revis, and Carrie Ryan, to name a few).
Not me, I vowed. I would not be able to live if my first book baby wasn't published.
I finished Mara, and even Mama Bear me could see its enormous, cannot be fixed, flaws. Talk about bottom of the barrel, if-I-drank-I-would, depressed. I'd wasted twenty months of my life, and I had nothing to show for it.
But then I started writing a new story, and I fell in love all over again (as I have with each subsequent child). And my writing this time around (while still flawed) was getting better. My story arced, my characters had somewhat realistic dialogue. I don't mind that book baby Mara is on the back shelf, possibly permanently. I've realized that the time and love I gave that manuscript, it wasn't wasted, it shaped me into the writer I am now.
So if you're working on your first book baby and the fear of it not being published is looming large, know that no writing you do will be wasted. Take it as a giant, learning experience. Allow yourself to move on and write better because of it.