IF THIS IS YOUR COUNTERTOP AND YOU CAN LIVE WITH IT THEN KEEP IT...JUST RESEAL OVER THE CRACKS. if THIS IS A CUSTOMERS JOB THEN I WOULD SAY YOU MAKE A NEW ONE.....SORRY TO TELL YOU THAT. JUST THINK OF IT AS A LEARNING EXPERIENCE. I KNOW IT SUX BUT THIS BEING YOUR FIRST ONE, YOU DONT WANT TO START WITH A BAD REPUTATION. NOW YOU KNOW TO PUT SCRIM IN THERE...OR REBAR...I PREFER SCRIM(NETTING). I CAN'T TELL YOU HOW MANY PIECES I HAVE HAD TO MAKE AGAIN IN THE BEGINNING OF MY CAREER. EVEN NOW EVERY ONCE IN A WHILE I HAVE TO MAKE PIECES AGAIN. ITS ALL ABOUT LEARNING AND TRIAL AND ERROR AND MAKING A GOOD REPUTATION FOR YOURSELF. GOOD LUCK
My vote would be to tear it out and re-pour. If you don't, more cracks will continue to show up over time. Concrete needs primary reinforcement.
Don't fret...I poured my first countertop three times until I felt I got it right.