Lots of confidence and feel the music, don't be scared to play out.

The fact that you were playing along with a video and noticed the added ornamentations is a good thing . . . it means that you are actively listening to what the player is doing stylistically. What you need to do is continue along this path. Actively listen to as many players as you can in the genres of music you wish to play, and play along with their recordings. The more you do this, the more aware you will become of where you can logically insert ornamentations. Eventually it will become second nature if you do it enough. It will also be good ear training for you (reading is important too--typically players will either be better readers or better ear players--you want to develop both these skills equally while you are young so that you can be competent in your career). Long before I wanted to be a jazz player, I was enamored by funk and fusion players and wanted to learn those styles. When I was your age--almost 20 years ago--the summer between high school and college I played along with my Tom Scott and David Sanborn LPs (CDs were relatively new at the time) for 6 hours a day, aurally transcribing melodies, improvised solos, trademark licks, ornamentations, etc. I would start at 1 PM, just after lunch, and play until 7 PM, and hang out with my friends at night. When school started in the fall, I had gained a good understanding of the style and had developed a vocabulary of phrases upon which I could call at any given moment (a lot of those still crop-up from time-to-time in my commercial playing to this day). As a result, I am the first guy that a good number of bandleaders, contractors, and producers think of when they require a saxophonist to play those styles. One final note . . . while doing this, never look at it as a chore but rather as a challenge. Above all, have lots of fun with it. Best of luck to you on your journey . . .