Is it okay for me to talk to a 15 year girl online?

There is a girl on Twitter from England I have a friendship with.
We talk about politics and culture and things of that nature.
Recently she mentioned that she would be 15 years old.

I told her I thought she was knowledgeable and wise well beyond her years and it didn’t bother me but I wonder if it would considered improper for me to speak to her.
Is it okay for me to talk to a 15 year girl online?
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