During all those years of penpalling, I've learned that if there's something I'm very terrible at, it is first letters. When you have to write to someone you don't really know much about, especially if you have to introduce yourself and you wouldn't enjoy ending up with a self-centered wall of text, there is a fun way to to do it with a twist!
Instead of a regular letter, you could unleash your creativity and craft a minizine (or a regular zine for that matter) all about you and your interests.
Here's some examples of what I've done in the past~ you can use a regular sheet of paper and decorate it with your favorite technique,
here. It has ready-to-fill pages with simple prompts (such as fav books, facts about you etc). Also, if it's your first time folding one, help yourself:
Have a great day,