I want to update my iTouch 4 to iOS 6, but I'm afraid I'll lose all the data on it. And when I went to iTunes, there was no button to back it up. HELP!!! :-o

Are you saying you backup it up to iTunes live specified here:

iOS: How to back up

Maybe here:

No Backup option

or

iOS: Troubleshooting backup issues in iTunes

If you have everything already in iTunes and you have synced with iTunes at least twice (to assure you have backup) then you should not lose anything. Upon completion of the update you will have an option to restore the device from a backup.

But, the update process will erase everything until you restore your backup.

Vital Resources For Your iDevice (Updating, Apple ID, and iCloud)

A. Upgrading iOS

1. How to update your iPhone, iPad, or iPod Touch

2. iPhone Support

3. iPod Touch Support

4. iPad Support

a. Updating Your iOS to Version 6.0.x from iOS 5

Tap Settings > General > Software Update

If an update is available there will be an active Update button. If you are current,

then you will see a gray screen with a message saying your are up to date.

b. If you are still using iOS 4 — Updating your device to iOS 5 or later.

c. Resolving update problems

1. iOS - Unable to update or restore

2. iOS- Resolving update and restore alert messages

B. Apple ID Support

1. Apple ID FAQ

2. Find your Apple ID

3. Recover your password

3. Change your Apple ID

4. Change your password

C. iCloud Support

1. What is iCloud?

2. How to set up iCloud

3. iCloud: System requirements

4. Using your Apple ID for Apple services

5. How to back up iCloud data

D. List of iOS Devices and What They Support

1. Identifying iPod models

2. Identifying iPhone models

3. Identifying iPhone models

E. User Manuals

1. iPads

2. iPhones

3. iPod Touches

Yes, that's normal because a restore will erase the entire device. Then it will reinstall iOS. When that is completed it will ask if you want to restore as a new device or restore from latest backup. Choose the latter.