Once you've analyzed the plan and the business are you now certain that its viable? One of the biggest benefits of doing a business plan is that it helps you discover if the idea is a good one or not.
Of course, this depends on whether you actually made a plan with thoughtful projections or is it actually a document constructed to pitch your idea to get a loan or other funding? One is a tool for you, the other is a marketing instrument.
My advice is that you need to take the plan to an established business person you know and have them review it. The insights and critiques that an experienced business owner will give can help you improve the plan or discover your errors.
Once the plan is fully reviewed, I would then take it to the least likely funder. A big commercial bank. Try to get an appointment with one of the more seasoned bankers and submit and wait for the rejection. Then call and ask for advice.
You want to put this plan through the ringer several times before you actually roll the dice and take it to someone who may actually approve you. If you go to a likely funding source first and they reject it, it may be hard to re-submit in the future.