I like what you have written. It is a bit overwhelming for someone who has never looked at the site.
If you are making a ʻcold callʻ, in the second paragraph I would just mention that they should take a look at your profile and notice how they can find your parents, etc.
Then I would provide the link to the Intro to WikiTree. And express your willingness to help them get started.
I am a minimalist, I think.