(1) Go sit down with the technical support section of one of the ISP's or hosting companies near you, if there are any. Often these ISP's host web sites as well as provide internet access, and can provide you with a wealth of information regarding what would be required on your end as far as security is concerned. There are site security certificates and a whole lot more to deal with and they can list requirements. I personally used this trick during my early days as web developer/designer (while I was learning) even though they were located 100 miles away so we had to communicate through email. Most often though, they're perfectly willing to teach you what you need to know.
(2) Later, when I finally found a hosting service that I liked above all others and used for all of my customers, I found that their technical support team was just as willing to help as the ISP was, if not more. Again, they're certainly in the know when it comes to security issues which they would ultimately be involved with. They'll also be able to help you with database issues which you'll eventually need for any e-commerce site.
(3) Also check out the various sites that provide the security certificates such as GoDaddy.com, Verisign, etc... They often have a FAQ section which explains what a certificate is, what it does for you, how it becomes intertwined into your site, what would be required of you, etc...
(4) Next, try talking to the merchant services section of a bank. You may need to try several banks until you find someone who is knowledgeable enough to speak with, but they can often answer a lot of your questions.
And finally, have faith in yourself. You'll do better than you think you will. After all, you recognize that you still have a lot to learn. You're not hitting the street with a know-it-all-already and have a piece of paper to prove it attitude. Selling yourself the first time will be the most difficult because you're inexperienced. So, get yourself a good hosting company and use the site to test/play/experiment/learn. Register your domain name. Set up a database. Learn FTP. Set up a dummy e-commerce site (without certs and merchant account for now, but in time you'll want it for your customers to use). You'll eventually want a site of your own anyway where you can set up sub domains to place customer files in for them to look at and approve. So, why not use your own site as a tester?