No, she doesn't need it. All she needs is her given ability to rip apart the fabric of space and time to make things go her way. That's why hardly anything she does makes sense, she makes it so she is able to do it even when it's completely improbable and impossible.
It's also why she usually breaks the fourth wall. In the process of ripping apart the fabric of space and time, she occasionally sees us!

She doesn't need magic because she is, clearly, more powerful than any higher power in the show. She probably doesn't show all of her powers so she can keep her true identity a secret.

Some Earth Pony magic, probably. Think about it- Earth Ponies are known for having connection to earth and bigger strenght than other types of ponies. Pinkie has Pinkie Sense, which means she can sense some sort of vibrations that tell her that danger is coming and she is EXTREMELY agile. Maybe that's Earth Pony magic "talking from her".

Every pony has magic or else Tirek could not have eaten everyponies magic. Tirek was able to eat Pinkie Pie's magic thus she has magic.