There's no way of knowing until you've had it done really! It's just a lottery. My first scope showed nothing at all - anywhere! My 2nd showed gastritis and a tiny area of Barretts. My 3rd showed gastritis and the same (1 year later) tiny area of Barretts. My symptoms at the time of the first scope were quite bad, and yet that showed nothing. My symptoms at my 3rd scope were maximal and after a bad period of being intolerant of medication - I fully expected some kind of bad news, even if just to say the Barretts had spread. However, things were exactly the same, despite a really bad period of reflux.
It's best to focus on general health things - things that reduce your overall risk of cancer. If you are worrying about Barretts you are worrying unnecessarily - they don't even know for sure what makes it progress. And for people who have developed Barretts, the commonest cause of death is not cancer, but heart disease.
I've said many times on this forum, if you're going to worry about cancer, then start worrying about the more common cancers first - you have more chance of bowel or prostate cancer than you do of oesophageal cancer!
Try not to overthink it - you'll soon be the other side of the test. And even if some Barretts shows up, there's no need to panic!