Seeds not germinating

I put 8 seeds in paper towels in a plastic bag, yes its damp but not to damp but theres still no tap root and i cracked one open and the inner part is looks like it soaked up the water then stopped. And im wondering if there to old or if i just need to wait longer?? its been 5 days

 

just room temp. if the inside swells like that does it mean there good?  there was a taproot inside