Hi Happybee
If you choose to report a change of circumstances to the DWP for your DLA they will more than likely suggest you move to PIP, or you can wait until you are invited to apply as you will be eventually. The length of time you have been on DLA has no bearing on when you are sent the letter to change to PIP.
BIS
Nothing on this board constitutes legal advice - always consult a professional about specific problems 
