Hi, and welcome to the forum. Good to "see" you and hope you enjoy your visits.
To change the font, go to your Settings app. Then select, on the left, the line titled "Mail, Contacts, Calendars." On the right side should be a line titled "Minimum Font Size." Select which size you want and you're done. Do note that you can't get any smaller than the smallest font offered in that section...
Hope this helps.
Marilyn