Not sure if you are meaning your currently on dla and looking to reapply in readiness of September.
My understanding is that dla will send forms around 20 weeks before your current dla ends, also with either dla or pip claim forms. Some areas already gone to pip other up to 2015/16 before they do.
Sorry if misunderstood and therefore answered accordingly wrong.
As far as I am aware (but I could be wrong?) you can try and upgrade your DLA components to a higher level but you cannot apply to go on to PIP earlier than they say that you can. As you will be contacted by the DWP when they are ready for you to apply for PIP (as far as I am aware).
I have pasted you the GOV.UK pages on PIP and DLA:
DLA will contact you 4-5 months before your current claim runs out, either to claim again or telling you that your new claim will be for PIP (Personal Independence Payment)
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