Jane is described as "uncomfortably shy and messy," often hiding behind plaid flannels and a tomboy persona.
She wants to shed her platonic status to capture the attention of a friend she has liked for a long time, but who currently only sees her as a friend.
Friend Zone Jane - Plain Jane (Season 1, Episode 1) - Apple TV
Like many "Janes" on the show, the premiere emphasizes that physical changes are only part of the process; the internal work of overcoming shyness is the real hurdle.
The climax of the episode is the "big reveal," where Jane finally confesses her feelings to her crush during their carefully planned date.
The episode highlights how sticking to a "safe" or comfortable persona (like the messy friend) can sometimes prevent others from seeing your romantic potential.
If you're interested in how the show evolved, you might want to look into later episodes like No Risk Jane or Wallflower Jane which featured more extreme confidence challenges.