Does she deserve it or did i mess up?

i dated like my first girlfriend in two years and it worked good for a while but then she went around telling people if her ex took her back shed dump me in a heartbeat so i did what any body would do and dumped her but now shes trying the im sorry it was all my fault technique and i have always been a guy who gives one shot and if you screw up you lost your chance and like i said i dont think she deserves another but whatd yall think