Is it too late to regain my dogs trust?

My female boxer dog has just turned 3 years old and since she was about 6 months old i've smacked if she's done something wrong. I always feel really bad after I do but I don't even realise when I am doing it...I haven't done it since last week and already she seems happier around me but sometimes when I go to pet her head she cowers a little bit.

Not too late, but you need counseling for anger management and some NON-Cesar books on positive dog training. Karen Pryor, Jean Donaldson, Nick Dodman.

in short no it is not too late. It may take a long time for her to regain your trust, probably a lot longer than it would take a human. Dogs are adaptive animals so if you keep on going on like that she will eventually become more confident with it. however she wont ever forget the feeling she has felt so even if you smack her after 2 years you may find that you are back to square one.

If you've been doing it her whole life, then she is going to fear you. It will take a lot of time and patients on your part to gain trust. I doubt you have ever really had any trust between the two of you.Some trust exercises I used with my dog are going on jogs together, playing with a favorite toy, just being together really. If she learns to trust you, and with some dogs it's very hard, then the head shyness will go away in time.With dogs, it's all about patients. Read up on some good trainers who use positive reinforcement. Just google them. There are lots of good books out there!If you have too much trouble with controlling your hitting action, find a new home for the dog. You and her will be much better off. I recommend not getting a new dog until you learn to control yourself.To answer your main question, no. It's not too late. It's never too late with dogs. They will love you and forgive you if you just give them the chance.Good luck!!!!!

Dog's do not have a short memory on being mistreated. She will never forget. She will never fully tust you again.