I'm 17 and I just joined the Army. I've decided to pick 19D and I was just wondering, would I have to fight in the front during a war?

There aren't really any fronts in our current Wars and conflicts. You will usually be operating out of a remote combat Outpost. If you have seen Restrepo, that is a good example.
I'm sure some other Cav Scout we'll get on here and explain the details of your job more in depth. Basically, you will be the eyes on a Target or enemy position. That could be inside of a Bradley Fighting Vehicle, or laying in the dirt on the side of a hill. In fact, your job should have very little fighting if you are successful. Ideally, the scouts do not come in direct contact with enemy forces, but instead observe them from a distance and possibly Direct other assets towards the target.

If you are concerned with actually fighting in a war I would say that you should not enlist at all. ALL SOLDIERS have a possibility of being involved in "front line" fighting; this is primarily because of the nature of the current conflict that we find ourselves in. That being said, you should really do your homework on what we scouts do before you make that choice. You may come to find that you want nothing to do with such a specialty.

welcome to combat arms Abigail. You are going to be a Cav Scout, guess what - you will go out in front of the tanks and scout for enemies, routes, and a host of other things - basically trying not to be seen by the enemy. So , it is likely that contact can and will be made, and yes, you will be required to shoot back at the enemy.