For a middle aged virgin, I think a gay bar would be the worst place to start. The poor guy will probably be so nervous. Gays are notoriously judgmental and even as a spry twink I always felt pressured to look a certain way, act a certain way, etc. Perhaps it's just a me thing but that's how I perceived gay bars.
I actually think that seeing a provider is a great idea to start off. You control the situation, they are there to provide for you. And best of all, they're experienced and if you're upfront with them they will surely be happy to guide you. I would probably start with a couple hours. 1 hour go by so fast, especially when you're having fun exploring. Some providers will even let you have the option to extend the session if you ask them before hand if that's a possibility, so you could start with 1 hr and extend if you're having fun.