Any number of things could be the cause. It could simply be something she learned on her own and now it has to be unlearned. Be patient and see what happens. Try lovingly rewarding her with a small treat for writing a in her name where it should be. Make it a game that lasts at least 2 weeks, then taper off the rewards. If the problem were to continue an eye exam might be in order.
thank you for the information,i never seen this before,she can write and recognize As but she will not use.them in her name.Gotta keep trying.Her.teacher hasn't said anything so i guesse I shouldnt worry so much.