I didn't know enough. My career didn't have enough awards marking the journey. The world didn't know my name.
At some point, I realized that a mentor is simpy someone who has been on the journey longer. Every experience leads to wisdom (be it "do this more" or "don't do that again" or "I wish I'd known") and wisdom can be shared.
And if wisdom can be shared, that means that anyone can be a mentor, and anyone can be mentored.
I've been fortunate enough to have mentors who are older than me and mentors who are younger than me. I also have a group of women who meet regularly (we're the Marketeers!) to mentor one another.
Never be afraid to seek out a mentor or to serve as a mentor - whether you're asked to or not. I'm glad I got over my fear and I feel that both my career and my life are better for it.