The Summer and Winter Maidens are a title for Fae at the very top of the court royalty. The Maiden, Queen, and Crone are considered the supreme rulers of all Faerie - which is ostensibly a matriarchy for that reason. The Queen is the role of the most direct power and sway, whereas the Maiden is essentially a Queen in training, and the Crone is a former Queen who has retired from her front facing duties. So, this pretty much means that the Summer Maiden is one of the top three most important fae in the Summer Court.

As for the Wyld Fae, they'll be a little bemused. The Ringmaster is a long time friend of the Maiden and is a Wyld Fae, but over all the Wyld Fae are a very diverse people with little central leadership. The impression one gets is that Wyld Fae are seen as formidable but wild beasts who refuse structure and usually only follow leadership once they've been drafted into either court. They don't mean this in a rude way, it's just the way the Wyld Fae are.