In 2015, when Caitlyn Jenner publicly came out as transgender on the cover of Vanity Fair, Orange Is the New Black actress Selenis Leyva felt uneasy. She thought of her younger sister, Marizol, who experienced harassment, discrimination and other painful experiences as a transgender woman.

“It was so wonderful for Caitlyn to finally live as her authentic self, but after reading the story I thought, ‘That’s not the reality for most people in the transgender community,’ ” Selenis tells PEOPLE. “They don’t have access to the best doctors, glam teams, adoring fans and covers of amazing magazines.”

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Selenis, 47, and Marizol, 29, have always been close — Marizol calls Selenis her “best friend and mentor,” and the pair lived together for a time while Marizol transitioned.

They decided to write a book sharing a different perspective of coming out as transgender. “Not one of being glamorous or famous, but the traumatic experiences we endure that we don’t really talk about,” Marizol says.

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My Sister: How One Sibling’s Transition Changed Us Both (out March 24) alternates between Marizol and Selenis’ narrations of growing up in New York, realizing Marizol is transgender, embracing her true self, and how the Leyvas handled Marizol’s transition.

Though the family is close now, there were several years when Marizol and her parents didn’t speak for other reasons. Now, Selenis and Marizol, a busy model, chef and activist, open up to PEOPLE about what they hope their book can teach others.

Marizol, you’ve endured a lot. How have you recovered and grown from the traumatic experiences you detail in the book? And Selenis, as an older sister, what was it like for you to witness these struggles and now, writing the book, discover new hardships Marizol faced?

Marizol: Activist work, cooking and self care. Of course, therapy has been extremely helpful. I wish I would have done this a long time ago, but there’s a stigma of like, “Oh I’m fine. I’m good. I don’t need any therapy to get better. I got this on my own.” Therapy was the most helpful thing to help me get by from all of these traumatic, painful experiences. But what also helps me is knowing that a lot of people are resonating with my story.

Selenis: It was really painful. I thought, ‘Did I do enough?’ But I had to ease up on myself because I really didn’t have the tools I have today. Maybe I could’ve done more, but I don’t have a magic wand. By sharing the challenges and mistakes I discuss in the book, I hope that will help another loved one [of a transgender person] be more present and turn to the right people for guidance.

Selenis, how did working with transgender actress and activist Laverne Cox on Orange Is the New Black help your understanding of Marizol’s journey?

Selenis: When I met Laverne, I remember thinking, “I’m going to watch her.” I thought, “How is this going to play out? Is this character going to be a respectful representation or is it going to be fluff and surface?” Laverne and I had our conversations, I told her I had a transgender sister. But I was so thrilled, not only that the character had so many layers and was beautifully written, but also Laverne’s ability to convey her thoughts and feelings in a way that made you listen that I knew would be really impactful.

Then about a year after we met, I got to present Laverne with an award and Marizol attended the ceremony with me. It was the first time that I declared to the world, to everyone in that room, that I had a transgender sister. It was also the first time Marizol had vocally said, “Yes, I am a trans woman.” It was through the platform that Laverne and that Orange Is the New Black had created for us.

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Speaking about other celebrities in the trans community, Dwyane Wade’s daughter Zaya recently came out as transgender. What was your reaction to the news? How important is Dwyane and Gabrielle Union’s unwavering support?

Marizol: When the news first surfaced on social media, I think a lot of trans people in the community were really happy to see families just stand up for their young daughter and support them in a way that most of us really didn’t have. To see that they’re giving a different outlook on 2020 and a different perspective to things is really important. It was really brave and sets a great example.

Selenis: In the African American community as well as the Latinx community, there is still taboo and resistance to anyone in the LGBTQ+ community. So when a family like theirs steps up and says, “This is our child. We love her and we are asking for respect and love,” that is the exact message that we want to convey with our book. If you have someone in your community, in your family, that is transgender or part of the LGBTQ+ community, then all we need to do to truly support them is to love, respect and protect them.

Marizol, what advice would you give to people struggling to come to terms with their trans identities, or how they can seek support?