You'll then have to upgrade to a dedicated server, which will cost you much more.
When it comes to platforms, the first question to ask is whether your site will be available exclusively on a web browser, or if you will have a mobile app.
If your niche is for people 50 and over, an app may be optional, at least in the beginning.
For any online business, your domain name will be your most important asset. If you're going after a particular niche, you can incorporate that into your name.
Just keep in mind that if you plan to go to other niches you'll have to get additional domain names.
Of course, there are companies with dating-friendly templates you can buy from too.