Hi again Esmeralda, and welcome to other newbies as well!

Don't worry too much about learning everything all at once. Just ride safely and read up and it will all fall into place.
You are lucky your bike is suited to you and your saddle isn't hurting!- lots of people have pain in the beginning due to ill fitting equipment.
Ride and have fun! Read about defensive safe riding habits in traffic though- that should be most important as you start.
Yes, I remember I had fitness walked 3 miles per day for 8 months before biking...I thought i was in great shape.... but NO! Man was I sore when I started biking!
It's all GOOD. Enjoy feeling like a kid again, and keep us posted on your progress. We want bike pictures too!