Can i use reading glasses if i'm 20/20?

Of course: 20/20 is the snellen fraction referring usually to your distance vision and indicates that you see the smallest standard line without the need for eyeglasses. But when you get to your age and beyond, you lens starts to lose its ability to focus at near and the reading spectacles will give you that power.

Reading glasses : Reading glasses are used for focusing your vision for close vision up to arms length. They become common place as you age over 40 to 50 as the focusing fibers of your eye lens harden with age fixing your lens in one position.

Yes: 20/20 is a measurement for your vision at distance. If you are 20/20 at distance without glasses, and nearing or over 40 you may be loosing your accommodation (ability to see up close). Reading glasses should work fine for the up close activities you need a little help with.

Sure: If you are having difficulty reading, or find yourself pushing reading materials farther from your eyes than usual, then you are probably ready for reading glasses. At your age i would recommend an over the counter pair at a +1.00 or +1.25 power. Remember to wear them in such a way as to be able to see over the top of them for distant viewing, or just take them off when you are finished.

Yes: The snellen test checks far distance. Reading glasses is for near vision.