Dianabol is a synthetic hormone similar to testosterone. Because of that, it stays in the system longer to do the things anabolic hormones do. Being a steroid hormone, it is slow acting, long lasting. The dianabol you take prior to your workout is not in your system for about ten days.
At age 19, I think it would benefit you best to seriously train for several more years and also let your natural endocrine system get established. If you start messing with your hormones this young, you will be doing this the rest of your life.
You will likely get more responses in the Pharma section.