Need advice regarding changing coolant

[Hamster]

Hello everyone!

My 2009 Toyota Yaris will be ten years old as of January. The maintenance schedule states that the coolant must be changed at 100,000 miles or 10 years. So, in a few months the coolant will need to be taken care of. I've done a search on this forum, and read a ton of threads about how to change the coolant. However, I'm still hesitant to do anything that I haven't seen done in person. I'm worried that something will go wrong, and I won't have anyone present to help me out. So, anyway, I have some questions:

1. Does coolant degrade with time?

2. The car, at the time of this writing, has just under 27,000 miles (the reason: I use public transportation to go to-and-from work. The Yaris is mainly used to get groceries and to do a little joyriding on weekends).
Can I get away with waiting a couple more years to get the coolant changed, or must it get done, regardless of mileage, at the ten year mark?

3. Is it best to get the coolant changed at a dealership, or could any independent mechanic shop do it if I provide the Toyota pink coolant?

4. Is a flush necessary, or is it just a drain and refill? If a flush isn't necessary, what should I do if I'm pressured into having one done?

I've never gotten my car serviced before, so I'm super nervous about. Any advice would be appreciated. Up to this point, I've done my own maintenance, like oil changes, changing the engine air filter, etc. Thank you!