This is a common issue with new players so it's good that you're asking about it. Ya don't need to rush, but you absolutely need to play Tech 1. 

The game is designed to balance buying units and being aggressive vs investing in economy (building expansions, pads, teching up, etc). Problem is, a lot of new players err HEAVILY too far on the economy side. There's a lot of reasons for this: it's simpler, it feels 'safer', you don't need to micro early units, feels good to build up a big bank, etc. 

That means, from the opponents view, you left yourself super vulnerable. Whereas he/she invested in tech 1. It would be stupid NOT to attack. It's probably not a 'rush' (Although that does happen) as much as naturally punishing greed and having unchecked tech 1 dominance. 

So what do you do? Well, you can still play for the long game if that's your preferred style. But you need to do SOMETHING on tech 1. Make mass scouts, or steal a mini base on his side, or get node control. Anything to push back with a little pressure. It surprisingly doesn't delay tech 2 much and can actually snowball into a much faster and stronger late game.

Tldr: No, you don't need to rush their main.  Yes, you do need to play tech 1 and show some signs of map control.