[SOLVED] How do I increase the font size of my post in Montezuma?

First, let me preface this post with the fact that other than borrowing a few books about WP from the library a month ago, I know virtually NOTHING about what goes on under the hood of a website. That being said, here's my question. If you have an answer, please explain like I'm a 2nd grader. Thanks!

How do I increase the font in my posts? I see the option for Bold, Italic, Strikethrough, etc, but there is no option for changing the size of the font. I need to make it larger so it's easier to read.

I went to the Add Google Font site that someone on this forum suggested in another thread, but it seems to deal only with headers, not the text in posts. At least I think that's what it says.

My site is www.MyBuckley.com.

Thank you in advance!
Sandra