How difficult is it to build a startup in Singapore? We don't come from financially rich backgrounds but my business partner and I would like to try building our own business. Are we too rash?

Why not continue with your day job, and build a business on the side? Many resources out there that encourages people to do that. Good that you have a business partner already you can hold each other accountable. With a steady income from your day job, you can probably afford to rent a cheap office somewhere: head there after work and weekends to "chiong" your business.
Motivation: Elon Musk and Jack Dorsey built two companies at the same time, maybe you can perform at your day job and build a company at the same time.

Hey Anon! I think anywhere in the world, it's going to be tough when it comes to building your own startup. So kuddos to you and your biz partner for wanting to try and start something of your own! I'd say make sure you have set aside enough capital to tide through the first few months or even years and have your own personal emergency funds set aside. Its not going to be an easy journey but definitely a fulfilling one.

I wouldn't say you're being too rash. In fact, now is a great time to enter the market in a covid19 environment because of low interest rates and the government is encouraging us to start new businesses (check out available grants and support here https://www.startupsg.gov.sg/). You would also have a stronger motivation to help you push through this difficult time compared to your competitors.

Good luck and all the best! :)