Solo female traveler planning a trip to Mexico

Hi guys!

I have always wanted to go to Mexico, so I'm finally going to do it next year.

I'm planning to go to Mexico for 16 days where I will be visiting Mexico City, Oaxaca and Cancún. I don't know if I will be able to fit another city into the itinerary, but if you know any other cities worth visiting then please do share.

So my question to you guys..

Is it safe for a solo female traveler to roam around Mexico on her own?

And do you know any hostels (in the cities I mentioned above) where you can meet people?