Forming a love for reading as a teenager or young adult is a great way to become an avid reader for life. Check out my recommendations below if you're interested in starting a new fantasy series that will whisk you away to the fantastical worlds woven by the words of each respective author.
The Chronicles of Narnia by C.S. Lewis - Lewis's children's novels are excellent fairy tale inspired stories with the strongest entries being The Lion, The Witch, and The Wardrobe, Prince Caspian, and The Voyage of the Dawn Treader are the strongest entries and are quintessential Portal Fantasy.
Legacy of Orisha by Tomi Adeyemi - Instead of the typical European inspired fantasy, Children of Blood and Bone draws heavily from West African folklore and traditions creating a unique setting and that is refreshing in a heavily saturated market. The content is directed at a high school level so it is can be a bit less accessible for younger readers.
The Scholomance by Naomi Novik - Novik's Temeraire series was an outstanding work of historical fantasy (with a couple rough patches) and A Deadly Education is as well. While there are some aspects that might have benefited from a greater degree of sensitivity, it seems to have been corrected in, all long hair is a bad idea in this monster ridden school for magic, the rest seems to have been approached well and provides an interesting approach to magic where the spells one can learn are limited by the languages one speaks. The premise of the novel is fantastic and Novik proves to be a strong author once again.
Inheritance Cycle by Christopher Paolini - The first book was written when the author was only 15, which means it has some weaknesses. Luckily, the monomyth is a strong backbone for any story to be built on and what Paolini creates is an excellent intro into epic and high fantasy.
The Mortal Instruments by Cassandra Clarke - Urban fantasy that seems to have drawn some inspiration from fantasy successes of the past, a dark lord with an evil plan and cult following, a special word for non-magical humans, and a chosen one. It's a proven starting point that holds up. The worldbuilding draws on a variety of religious and mythological sources from around the world and creates an intriguing blend to journey through as the various relationships and romances develop.
Harry Potter by J.K. Rowling - A landmark in modern fantasy, it reinvigorated the genre and brought it into the public eye. The core books are a great jumping on point for young readers, just don't pay too much attention to the author on Twitter.
Percy Jackson and the Olympians by Rick Riordan - Greek myth inspired YA fantasy targeted toward late elementary school through early high school, which is admittedly a wide range, Percy Jackson and the Olympians is a highly accessible series of books with writing and characters that improve as the series moves along in much the same way that happens in Harry Potter.
Rise of the Empress by Julie C. Dao - Dark fantasy inspired by East Asian folklore follows a female anti-hero on a journey to gain power. Comparison's to R.F. Kuang's The Poppy War are understandable at first glance, but this one came first. The magic systems in place are unique but not unfamiliar to those found in dark fairytales. Only a duology, this is an easy way to sample the Grimdark genre without being buried in thousands of pages for those who don't want to commit to an epic like Martin's A Song of Ice and Fire or even Kuang's Poppy War Trilogy while still fulfilling the desire for something a bit more tragic than most of the other YA offerings.
The Folk of the Air by Holly Black - Political intrigue is a popular subject in the fantasy genre, Black's take on the subject draws inspiration from the tales of Faerie Courts in order to build its intrigue.
Six of Crows by Leigh Bardugo - A fantastical take on an Ocean's 11 style heist. The diesel(?)-punk fantasy veneer over a tried and true heist formula is enough of a refreshing take to make the story unique in genre fiction.