You need to be able to get feedback on your product as quickly as possible, so my advice is to choose the technology stack that will allow you to build a prototype efficiently. There's no right answer here: for some people it's LAMP, for others it's node, for others it's a Windows stack.

Worrying about the technology at the stage you're at is a red herring: worry about the product, the problem it solves and the user experience of your solution, and get feedback you can iterate on as quickly as possible.

I'm a serial startup CTO who's now a startup founder and CEO. Let me know if I can help.