The actual distance shouldn't be a problem for you unless you have some joint problems ... but, you do need to be comfortable SITTING on your bike for short rides, first, of course -- ensuring you have the right saddle for you based on whatever riding position you choose (upright, or not) is definitely important.
As others have noted, your main concern will be having sufficent water + easily digested food (e.g., fig newtons). Charity rides frequently have 'feed' stations ... but, you'll want to carry at least one water bottle on your bike (or, use a hydration pack).
Cycling shoes will help.
Modern cycling jerseys are made with a fabric which breaths better than regular fabric.
Sun glasses will help keep the wind out of your eyes ... I wear goggles when it gets windy.
A helmet is a good idea, if you don't already have one ... whichever helmet you get, you want it to be comfortable when you are wearing ... less expensive helmets seem to have fewer vents ... vents are a good thing, but you don't have to spend more than about £40 (retail) for a reasonably good helmet.
Don't forget the Sun Screen!