The funny thing is that Facebook already has so much of our older data that they can use, even if you delete your account now you never know what they will do with it in the future. In 2008 when I got peer pressured by my work colleagues by saying that if I don't create an account then they will do it for me and I didn't want to be misrepresented on where I knew most of the people already were.
saying that if I don't create an account then they will do it for me
I would report the hell out of them, both to Facebook and HR. That's literally the definition of identity theft.
Although the point is kind of moot - because of all the people who know you, that do willingly share their everything (including their phone contacts, photos etc), Facebook already has a You-shaped hole, even if you don't have an account.
So when I got pressured into creating a Facebook account (not as badly as you were though), I was so creeped out by the amount of data they already had on me, I immediately deleted my account. It felt like being invited into someone's home for the first time and seeing a stalker shrine dedicated to yourself.
Although the point is kind of moot - because of all the people who know you, that do willingly share their everything (including their phone contacts, photos etc), Facebook already has a You-shaped hole, even if you don’t have an account.
My favourite bit of the WhatsApp terms and conditions is where you agree that you have permission to share the information from your contacts. So, even if you go out of your way and tell WhatsApp you object to them using your data, someone else will supercede that when they accept WhatsApp's terms.