Hailey, 
 
That's a tough question. Everyone is different as to how they handle different situations. 
 
I will definitely agree that it can snowball. 
 
A limited amount of kissing is not sinning. But if you find yourself kissing more and more and more be very aware that it is a slippery slope and simple kissing can quickly lead to things that you don't want to do. Maybe the best counsel is for both of you to sit down when you are both thinking logically and rationally and then determine where exactly is the line you want to put for yourself. That might be no kissing at all or it might be something different. That will be up to you. Then identify exactly what you will do when you approach that line. If you both can agree on what your "line" or standards are - and then both of you will be working to that standard and helping each other keep the standard you will have at least put some safeguards in place.  
 
If you find over time you are crossing that line - or even changing that line - then both of you need to stand back and re-assess what is happening.  
 
I would also encourage you to read the church pamphlet "For the Strength of Youth". Also in the April 2010 New Era (church magazine for teenagers) there are numerous articles talking about dating, etc. (These can be found on the church's website at www.lds.org) 
 
Love and romance are beautiful things, but there is a time and a season for everything - including romance!