The actress recently landed the role of Ian Beale's wayward daughter Lucy, who returned to Albert Square last week in time for Pat Evans's funeral.
Revealing how she got into acting, Bywater told The Mirror: "I went to a drama school on Saturdays and then I was taken up by an agent. I've done two films and some adverts, so this isn't my first job but it is still a very big deal.
"[Joining EastEnders is] pretty overwhelming. I was really nervous as everyone knows each other and it's like a big family, but they're all really welcoming."
The 17-year-old revealed that Shona McGarty (Whitney Dean) has been appointed as her mentor on set, while everyone else at the programme "has been like a mini-mentor".
Bywater has taken over the role of Lucy from Melissa Suffield, who left EastEnders in 2010.
Discussing the challenge of playing an established character, Bywater said: "It is quite difficult as everyone knew the old Lucy and what she was like, but hopefully I can put my own stamp on the character."
EastEnders fans will see Lucy return to her mischievous ways this week as she launches a scheme against Ian's new girlfriend Mandy (Nicola Stapleton).
> EastEnders' Nicola Stapleton promises Lucy return drama
> EastEnders' Mandy is no fool with Lucy, says Nicola Stapleton
> EastEnders: Lucy and Mandy's war begins - Spoiler Pictures
> EastEnders' Melissa Suffield: 'I've moved on'
> Read more EastEnders spoilers and news