Ask HN: What is the fastest way to code a website?

I have an idea for a peer-to-peer startup which needs an e-commerce/craigslist kind of website. I am a good programmer, but I've only used C++/Java/Python my whole life and worked only on the platform side of non-internet products (Think of Desktop applications, MS Office, etc). I've never used any of the modern web frameworks nor know much about scaling up a website, services etc. When I look up on the web, there are literally tons of frameworks, languages, and choices to make. What would be the fastest and the most effective way to code a website? Also, I might've to scale it up in future, so I don't want to make the mistake of using esoteric or dead languages.