E-Mail question

I have a question about email guys. So whenever I am in my email and I want to reply to a message or create or compose a new message I click on new and it brings up the window but everything in the box is very small, how do I change it to bigger fonts, ect. Thanks in advance.

Bigger font's can be made by opening the "Fonts" window command+t

Also, Mail, Preferences, Fonts and Colours.