I know I've often said this before, but dogs don't have to be a binary I have a dog/I have no dogs in my life split.
There are lots and lots of ways you can build up your exposure to dogs and get a feel for some of the lifestyle changes, as well as getting your doggy fix.
Firstly, do any of your friends have dogs? Would they be willing for you to "dog-sit" while they have a night or a weekend away? Being an honorary dog auntie is actually lovely as you can build up a great relationship with the dog, have lots of fun, but not the expense. 
Secondly, volunteering. Most areas have rescues that are desperate for more volunteers. This can range from walking dogs in kennels, to helping out at events, cleaning kennels, baking cakes, stewarding at shows, even updating the website! Get involved and you can get lots and lots of hands on exposure to dogs and be around them.
You can also volunteer to do things like homechecking and transporting dogs. Dogs often need to be moved to a place of safety away from the area they have come from, or to a new adopter/foster home. Transport networks exist that move dogs between rescues and safe homes. For longer journeys you can usually claim mileage/toll fees.
Thirdly, Cinnamon Trust. This wonderful charity matches up dog walkers with dog owners who are either elderly, frail or terminally ill. By going in and walking the dog, you are helping the dog to stay with their owners. It's a great idea and you can commit to as little or as much as you like. You also have the great satisfaction of helping an older person.
Fourthly, fostering. This is great, as you have a dog in your home for a short time while it gets assessed and then adopted into its forever home. One of the hardest foster homes to find for most rescues is homes where there is no other dog, yet these are often needed - for example, where a dog might be recovering from an illness or is nervous around other dogs. If you get in touch with local rescues, they will often have information about fostering on their websites, and most are only too delighted to welcome you, answer your questions and show you the ropes.
Any of the above will help you decide if the joys of dog ownership are for you. I think that if you really love dogs, you'll find yourself gravitating towards them anyway. If not, you've done some good and found out before taking an irrevocable step.
Good luck! 