I disagree with Maulik V's answer.
She mixes with all types of people is a different construction than
They are our type, the latter of which (in my experience) almost always refers to some sort of attraction (romantic and the like).
all [different] types of people is like saying
all [different] colors of people, but saying
she is your color is a different construction than
your type since "type" here has a different colloquial meaning indicating compatibility in a romantic or sexual nature when used in this way.
mingle as used here is fine. As per a question in the comments, it's neutral, so neither formal nor informal, and would be appropriate in most cases where "relaxed meeting of (potentially new) people" is meant.
Some examples of what you could change the sentence to:
When we go to a museum we can mingle with some like-minded visitors and make friends with them.
When we go to a museum we can mingle with the same sorts of people and make friends with them.