Formating text to include calculated date.

I have been looking everywhere for a way to format a text block to include a calculated date. I am not an html programmer, but I have attempted to insert php and html code, I found on the net. Since this is my first time using WordPress, I imagine it is because I do not know how to insert it.

What I would like to do is have a text readout that say:
We have been around for x years.
I would like x of course to be the difference in year between a set date and the current date.
So far what I have tried is to input the code into the visual field of the textbox.
I downloaded code snippet and set up a snippet, but have no idea how I call the procedure from the snippet….. any help would be most appreciative. Again I tried google and searching here, but could not find an example of how to do this.