Is it normal to send anonymous porn emails to my gf?

I create a new fake email address, I create a new email with porn images found on the internet of the things I like and I send it to my girlfriend.

She doesn't know that I send her these emails because I give them some generic titles(like advertisements) and she usually opens them(I send emails using the options that I recive an email when she reads it).

I like to do this like near the midnight when She goes to bed so maybe she masturbates with the porn images that I have sent to her.
I think she thinks it's some kind of advertising emails and we never talked about porn.

Is this normal?