How do I keep my email message at font size 14? It always defaults to something to small to read when typing g message.

Mail>Preferences>Fonts & Colors

Set the size in Mail > Preferences to whatever is best for you. This setting does not affect what the recipient sees at the other end.

The issue is the reversion to default. I want t o keep the new setting,

I have macular degeneration The default type size is useless.

What you set in Mail > Preferences > Message Font should stick. I have mine set to Helvetica 18 and that stays. What setting are you trying to make and what is is going back to?