So I'm not Mary Frances. I'm her husband who is force to deal with this opaque and obnoxious equipment (iPad). With the iOS 7 update she could no longer follow web links by tapping them in an e-mail (it did work from a web page). After an hour of web searching, experimenting and rejecting the offer of an answer from apple help for only $20, I found that, if in settings/safari, you turn off the "Do Not Track" button, the ability to follow links in an e-mail by a tapping is magically returned.
Flash! I just went back to the ipad and turned on the "Do Not Track" button -- just to test my discovery. Predictably (by my cynical myself) you can still open a link in an e-mail, so I don't know what's happening/happen. But I'm not surprised.
You might find more help on the iPad forums: https://discussions.apple.com/community/ipad
This forum is for OS X which has little in common with iOS.
I don't have any problems with links with that setting on or off, so likely a re herring.
Have you quit Mail and reopened it?