Will my PT score have a negative impact on my chances of selection for 153A?

It will depend on your board.

Boards that I've sat on agreed that PT is not the key to success as an Aviator. Warrant officer recruiters have shown dismay when we, quite regularly, have turned down candidates who are 300 PT studs. I'm more impressed if you know the standard army airframes and their mission in the Army. You would be surprised by the volume of candidates who claim a "lifelong dream" of becoming an Army Aviator but don't know the difference between Attack and Air Assault operations.

75% or better in each event is fine in my book.

You're "supposed" to take a PT test within 30 days of PCS and/or starting WOCS and yet candidates still show up and fail the initial PT test during inprocessing at HHC. Don't be that guy and you'll be fine.

PT should be alright; you’ll improve your score while at WOCS. However continue to work on it. Also remember that the ACFT has taken the APFT’s place for initial entry training courses (WOCS is considered initial entry)