Try not to let it overwhelm you. But, you're right there is alot more to cycle-commuting. It's a lifestyle committment to a certain degree. The benefits of perseverance far outweigh the challenges of the learning curve, though. When one begins to view a bike in terms of utilitarian use as opposed to recreational or a hobby it takes on a whole new character. Suddenly, you'll find yourself appreciating good componentry, materials, etc. Learn as much as you can about being your own cycling mechanic. Local jr. colleges, adult ed programs, local bike shop or bike co-ops often offer basic maintenance classes. Take one, you wont regret it.

Also, don't be afraid to invest in your bike(s). That includes tools, etc. It'll pay off in ways way beyond losing weight or reducing your carbon footprint. There's an intangible internal confidence that manifests as a natural outgrowth of daily commuting and being capable of doing one's own maintenance or roadside repairs. It's hard to explain, but you'll know it when it happens.