By all means, go to your local pro shop. If you aren't sure about the one in your home house, ask some of the better bowlers in your area where to go.
If you're at all interested in bowling more than once in a while and you have no major physical problems, it's worth the effort to learn to throw a hooking ball with a fingertip grip. A properly fitted ball will not be difficult to hold on to, fingertip or conventional (fingers up to the second knuckle).
If you're not exceptionally weak, I would not go with less than 14#. If you can use some 14# house balls, you shouldn't have any trouble using a 14# ball that's custom fitted for your hand.
Talk to the local driller, many of them have packages where you can get an entry-level ball (usually a Power Groove, Tropical Storm, Scout,... or maybe a plastic ball), a one-ball bag, and a pair of shoes for a discounted price.
SH