Planets are not born in their final state; before reaching a more mature and stable phase, young planets are significantly altered and reshaped by their environment. The first few hundred million years are thought to be the most formative, but planets in this age range are also the most difficult to identify and characterize. Instead, research has focused on inferring the history of exoplanets through patterns in the population of older systems. Now this paradigm is shifting thanks to the discovery of Earth- to Neptune-size transiting planets as young as 10 Myr. Statistical analysis of this sample has given us direct constraints on the timescale for exoplanet migration, ruling out disk migration or in situ formation for the majority of Super-Earth to Neptune size planets. Further, follow-up of individual systems has given us the first glimpse into how planetary atmospheres change over time, including measurements of atmospheric mass-loss.