Genevieve,
The first thing is to register a web address that reflects your shop, location an/or both. Hopefully, a domain squatter isn't currently holding it ransom. Our host here at FlowerChat offers that service at a very, very low pice here:
http://www.rkfdomains.biz/ (I have several domains registered there and the service is excellent.)
Next you'll need a host and site - some companies do both. A site can be as simple as a single page along the lines of a Yellow Page ad and can grow from there. The less you know about a website, the more you need a developer that speaks 'flowers' and can handle all the routine tasks for you - like the guys at Digital Thoughts.
Do you want to have online shopping or just a site for folks to browse in?
For most shops, a template-based site is the way to go and is definitely the most economical route in the long run. In addition to the wire services, you can get templates (with various levels of customization depending on the package) from a number of companies. (If I can find the thread where they're discussed later, I'll post it.) The more well-known companies have wire service images pre-loaded and you can just change prices as needed.
If you intend on using your own photos, you can still use a template or build your own site through companies like Yahoo!, Amazon and others - but they take a lot of time to keep up-to-date (with some having fairly high fees).
You'll need a way to retrieve your orders from the site so pick a company that makes it easy.
Heck - You're out on the web and found your way to FlowerChat so you can't be a geezerette.
I suggest you go back through previous threads in the Web Development forum since there's been much discussion about naming sites and choosing webmasters and hosts.
Hope this helps.