Hi! Ever since I was a kid I was always fascinated by games, I believe we all were and still are. There was a certain mystique while playing a game, something that helped us all in someway. I'll never forget playing the original super Mario bros and then going to super Mario 64 and wanting to collect all the stars just to see Yoshi! This is something I want to replicate, I want to make a game that people will enjoy. I know absolutely nothing about game design and I don't want to come off as ignorant when I say I want to make a large open world game. I understand it may be an insane amount of work, possibly unrealistic/impossible for a small team. But that's what I want to know, if anyone could be real with me and tell me the realistic amount of time, people, and money I would need to make a large open world game. I understand that it being my first game is unrealistic but that's my end goal and I just want to know the specifics of it. I greatly appreciate anyone who gives any tips or information. I'm grateful that such a community exists. 

Depends on experience and how you go about it. In theory, if you were a decent enough programmer, you could procedurally generate all you want. That's how Daggerfall was made. The drawback, of course, is you will have a possibly flat game in terms of content.

Could go the Less is More approach such as Skyrim where they scaled everything down so they could give personal touches to everything. The drawback of that... that takes time depending on the scale.

So, if you want realistic: Skyrim took  roughly 5 to 6 years to release after Oblivion was released. I don't know how many are in their team, but I imagine it's in the 100s. They probably spend over millions developing this game. 

However, there is a indie game called Dwarf Fortress. While not entirely open world, the scope is massive. Developed mostly by two people. The project is still ongoing since 2002.  That is roughly 15 years. Now, they had made other things before this, so they did not start new.

My advice: start with a small game. Understand what you can and cannot do before you attempt anything large, because even if you managed, it won't be very good due to the lack of experience.