Thanks A lot for your answers.
A few more questions:
1.
Where can I find out how much space iOS 8.2 will take up on my phone.
2.
Also, how can I verify how much space my current ios version is taking up on my phone?
It shows up under Usage inside settings, but I don't know if that number is really true.
**3. If I don't like ios8 I should be able to delete everything from my phone, then do a full restore of my data and iOS 7.1.2. Right??**
(any other ios 8 update know how would be appreciated.)
I'm sorry but I believe you can't really get the information your looking for in question 1 and 2.
And once you update your balls deep. You can't go back and a restore would not help you because the OS on the phone is not part of the back up. Also a little bit of that update know how

you can not take a back up and restore it on a older version of iOS. You could however still take an older back up and restore that but Apple only saves 3 back ups.
Little bit more update know how: If it's space your concerned about I suggest trying a clean install. In my experience clean installs tend to free up a bit of space. Not to much but enough.
Here's how
1. Back up phone (Settings > iCloud > back up > back up now)
2. Wipe he phone clean (Settings > general > reset > erase all content and settings)
3. Just sorta skip though the set up process. Really the only thing you need to do is connect to wifi. For Apple IDs and such just keep pressing skip where ever possibe and set up as new.
4. Update to iOS 8.
5. When it's done you may or may not get something that looks like the set up screen you saw earlier (sorry I don't know if you do or don't). If you do again just make sure your connected to wifi and skip through that. Then you whip the phone clean again as you did in step 2.
6. Actually go through set up process and make sure you restore iphone from the back up you did earlier.
7. All you stuff will start to load.
PLEASE NOTE: This could leave you with out a phone for a few hours. While updating to iOS 8 you will not have any of the stuff that was on your phone before. As well as once you do go through set up it may take a while to load back all of your apps, music, and photos.