I think you should start wearing reading glasses, as you will delay it then the power of lens can be increased.As we do read eBooks,PDFs files from computer,as we have to concentrate and that can damage our eyes but wearing a reading glass will save our eyes from getting strain. I usually wear reading glasses at the time of reading and my doctor suggest me to purchase from http://www.citysunglass.com/,as their glasses quality is good.
I would suggest you get a second opinion before you get that pair of glasses. Most people your age don't need that type of glass and it may even be a progressive bifocal.
See an Eye MD ophthalmologist. When you are seening ask that they do a refraction by "fogging" you and seeing how much farsighted correction your eyes will take. Be sure to take your glasses RX in from the first eye doctor and show them.
JCH MD
Forgot to add more info...
At the bottom of the prescription, It says ADD +0.25 FOR PAL