Lifespan of Starlight Series by Thalia Kalkipsakis

It already lies dormant within you: the ability to move within time. In 2084, three teenagers discover the secret to time travel. At first their jumps cover only a few seconds, but soon they master the technique and combat their fear of jumping into the unknown. It's dangerous. It's illegal. And it's utterly worth it for the full-body bliss of each return. As their ability to time jump grows into days and weeks, the group begins to push beyond their limits, with terrifying consequences... moreIt already lies dormant within you: the ability to move within time. In 2084, three teenagers discover the secret to time travel. At first their jumps cover only a few seconds, but soon they master the technique and combat their fear of jumping into the unknown. It's dangerous. It's illegal. And it's utterly worth it for the full-body bliss of each return. As their ability to time jump grows into days and weeks, the group begins to push beyond their limits, with terrifying consequences. Once you trip forwards, there's no coming back. less