Earlier quoted context omitted.
That definitely looks like an impactful year from the graphs there. I think if I had kids I wouldn’t let them on such sites until 16/17 or never. Granted, I have a strong opinion against social media before this data.
How would you handle it if they begged, pleaded, and explained how all their friends use it and it'd be social ostracism to not use it? I'm not a parent yet but I dread this situation. I'm good at denying urges personally, so I'd tell them desire is a constant part of life, we can't always get what we crave. Further, I'd state actual facts about girls mental health, they will see and be exposed to unhealthy mindsets…
Having been on both sides of this, as a teenager and having saw my siblings go through it, I don't envy you either.
But I can talk about my personal experiences. I was very introverted as a kid, and tools like Facebook gave me a bit of social autonomy and confidence, and it absolutely strengthened my in-person relationships. I know others that feel the same.
Not being contactable via the internet definitely can cause social ostracism, but a reasonable middle ground for me is something like Discord or WhatsApp, which is semi private and avoids the toxicity of The Feed.