Thanks for the advice everyone. I just found out that the rescue doesn't really know how old she is, they estimate anyone between 3 and 5 years; so she's a lot older than 3.
I took a closer look at her eyes, there is a small section that is already matted on both sides.
I just started using a warm damp cloth to clean it out, I wasn't able to clean everything out. I will have to be doing it every day until it's gone.
I also had a question about collars. I just got a new collar for her and she's been rubbing her neck and her entire body on my carpet. I wasn't sure if this was a yorkie thing... or just her new collar. She only does this maybe 2-3 times a day.
Thankfully, I'm planning on calling the vet tomorrow to make an appointment soon. Since she's a rescue, they only did basic testing.