Backpacking can be a really fun adventure to go on. However it can only be so if you go prepared. Not everyone went on such a trip, and the first time can be scary or stressful. Next you can read some tips for your first backpacking adventure.
Don't be overzealous
A backpacking adventure can look amazing in movies or TV shows, however the reality is very different. Many first timers make the mistake of planning a trip that lasts for too long, or planning on walking too many miles a day, only to realize they can't do it. It is better to plan 1 or 2 nights out, but definitely not more than 3. Some people have the impression they can walk more than 5 miles a day, but it is more realistic to plan on covering half or less of the desired distance.
Don't go on a spending spree
Usually first timer backpackers want to do it because they saw others having so much fun, and felt inspired to follow their example. This is great, however spending thousands of dollars for an activity you might hate is simply not worth it. You'll be better off and happier when renting and borrowing the backpacking gear from friends, neighbors, or specialized stores. Make sure to test your gear before leaving to you'll know it is not broken and make sure you know how to use it. Investing money in the right tools should be done only after you know for you you like it. You should make sure you don't lose any of the borrowed items.
Beware of over-packing too
Many people make the mistake of packing too many things they will not use once, but skip on the items that would matter. Check the weather and see if it will rain: any chance it might, means you need something to keep you dry - just forget the umbrella. Pack more pairs of underwear, a pair of wool socks, and a top that will keep you warm at night. Fabric and quality should matter more than the appearance. Further more, take clothes that can be worn for a few days in a row. Water and food should be more important than a cute shirt you won't be able to wear.
Using the toilet, when there is none
This tip is most certainly over-looked, but shouldn't. We all need to use the bathroom at some point, but if you're in the wilderness you're miles away from any decent toilet. You can't go unprepared, so you will need a kit: toilet paper, 2 zip-lock bags, a trowel, and hand sanitizer. You will use the trowel to dig a small hole in the ground, do your business in it, and then replacing the soil. you should throw the used toilet paper in one of the bags, and keep the trowel in the other bag. Even if you don't touch anything, your hands might still feel dirty, therefore the sanitizer will sure come in handy.
The last tip you should be aware of is that your first experience should happen on a beginner's trail if you want higher chances of a good time.