Introverts are very private people. Anything they put out to share is calculated. That's why they find it funny when people think they know something about them. Nope. Not a chance. Trust me, you don't know a thing.
Don't ask introverts "why can't you make a decision right now". They just can't. That's not how they operate. They like to take their time. Think and reflect and contemplate. Draw the pros & cons. The in & outs. Map out everything mentally. If you rush it, it's a no. Be patient.
Introverts don't force people to choose them. It's just not their nature. They're fiercely independent. Yes, they enjoy the company of a few, but they don't "need" people. They wait. They watch. They quietly observe. And if they like you, you're in for one hell of a ride.