It’s the question every out teen dreads: ‘Are you sure you’re actually transgender?’

At best, it solicits an eye-roll and a well-rehearsed answer; at worst, further months of self-doubt and stress.

14-year-old trans girl Cassandra proved once and for all that teens aren’t ‘too young’ to understand their own gender identity, responding calmly and helpfully to others’ prejudices and misunderstandings on Reddit.

‘Some people can be assholes, but I’m simply amazed at how many people online have jumped to my side as soon as anti-trans things were said,’ she wrote.

Ajaxthelessr asked: ‘Are you sure youre actually transgender? According to Dr Paul Mchugh, former Head of Johns Hopkins Psychiatry, 80% of adolescents grow out of transgender feelings. How would you deal with transitioning back?’

Cassandra’s simple response?

‘Yes.’

She went on to explain: ‘I have read some basic things on him, IMHO he knows nothing. He uses the word “transgendered” which isn’t even a real word, it’s like saying, “Mom, Dad, I’m gayed”.

‘He suggests not letting kids transtion and making them go through an unwanted puberty. Google Leelah Alcorn. That is not an isolated incident. 41% of trans people attempt suicide at some point during their life. That’s a shockingly high number.

‘He claims its a mental disorder, when recent studies have shown that it’s not a problem with the brain, it’s a problem with the body. Basically what happens is in the womb, a fetus is female by default. If it is supposed to be a male, the mother’s body will give it two “doses”(I can’t think of a better word) of hormones, one to make the brain masculine, and one to make the body masculine.

‘The reason trans people exist is because we only got one dose of hormones. MtFs get one to the body, and FtMs get one to the brain. Arguably we could try to fix the brain, but it is far easier to fix the body.

‘To add to that, I have known since I was three. I think most people would agree I didn’t learn the word transgender until about 11. I have also been diagnosed with gender dysphoria.’

When the ugly question of whether or not Cassandra will ‘truly be a girl’ reared its head, fellow Redditors stepped in to defend her.

‘It’s not easier to fix the body’, Beastabuelos wrote. ‘You can never truly be a girl. At least not with today’s tech/medicine. Nothing against you, it’s just true. You can’t have a real vagina or womb or have a baby or anything.’

Weaselgregory13 responded: ‘You can truly be a girl. You are truly a girl. You have a girl body because you are a girl. Never listen to people who try to invalidate you or your identity, they are wrong.’

In an attempt to answer the question of gender definitions and societal gender roles, Cassandra shared her thoughts on the difference between sex and gender.

‘Gender is what is in your brain. Sex is your body. You are the only one who can define your gender,’ she explained.

‘Gender is who you are, like your soul.’

Speaking to GSN following the online chat, Cassandra explained what she’d learned – and urged the US education system to do more to educate young people about gender and sexuality.

‘Last time I checked, schools (at least in the US) teach zilch about gender identity,’ she said. ‘It’s not nearly enough.

‘People telling me that I’m fetishizing lesbians and things like that were really upsetting, particularly because I have a crush on a straight girl.

‘On the flip side, I was amazed how many people were OK with me being trans.’