Don,t start over learn something. You can read till you think your the Master cannabis scholar and still make stupid mistakes/over-do things because nothing beats actually learning from the plant itself, making mistakes, correcting them ect. you will learn to recognize signs, your plant will tell you when things aren't right. For instance that huge internode gap in your plant plus yellowing lower leaves was telling you that she was hungry, you starved her a bit during veg, so the normal yellowing process of nitrogen being used in older fan leaves 4 weeks in bloom is more pronounced..keep her going. A qtr strength foilar spray of some nutes during lights off/just before lights off may help a little, some might argue, just what I would do..just try not to spray the buds. Previous advice about pulling leaves is golden imo a leaf still has something to offer the plant until it can be removed with a gentle tug, the plant knows best.