I'm a 70 yr old woman. Is that too old to be having juvederm injectIons?

Your age will not preclude you from having fillers.  There are many 70 year olds who may not want or need surgery but have some lines or hollowing that can be helped with fillers.  Some people however will have so much volume loss at 70 that a tube or two of filler may not be noticeable.  In these cases you may be better off doing some sort of a surgery.  Get a couple of opinions.  The antibiotics will not affect the outcome  

When assessing a patient as a candidate for Juvederm an experienced injector will evaluate the face regardless of age. Schedule a consult with a Dr or expert injector to obtain their recommendations. Also, the Dr will discuss a full health history to ensure Juvederm is the right product for you. 

You are certainly not too old to undergo treatment with fillers.  In order to achieve best outcomes, you may well require placement of certain products deeper in your face to replace volume that has been lost over time as well as more superficially placed fillers to treat wrinkles and lines.  Some patients choose to undergo treatment is phases so as to avoid a more dramatic change in appearance whereas others prefer to have full correction at their initial treatment session. 

I have done Juvederm in 80 year
old and older patients with excellent results; and as long as there is no
current systemic infection you are fine getting the juvederm even while on
antibiotics.

Hello, you are not, by any means, to old for Juvederm injections. However, there are many different options that may be more suitable and cost effective for you. I recommend that you find a board certified plastic surgeon to consult you on what would be your best options. Best of luck to you.