When posters talk about the pipeline they are usually talking about the number of students flowing into UPT. Right now you are talking about predicting almost a decade away from entering UPT. ...figure you won't graduate until you are 22, and may wait 6 - 9 months before you start UPT, thus probably will be 23 when you start.
What is occurring right now regarding the pipeline is they are operating at 110% capacity. They can't get them through fast enough to fill the amount of pilots leaving to go to the airlines.
There is a converse relationship between retention and the economy. For years the airlines did not hire, thus pilots did not leave at the rate they are now because the airlines are now hiring at a frenzy. Eventually though airlines will slow down and pilots will likely remain at a higher rate than they are currently. Thus, in 2025 when you are going to enter UPT the pipeline might need as many pilots as they need now.
As far as becoming a fighter pilot that is also going to depend on a lot of things. Statistically the odds when you add in start to finish are not high to become a fighter pilot. Commissioning in the AF is step 1. Being medically qualified is step 2. Pilots must pass the FAA FC1 physical. Step 3 is being in the top 25% of your UPT class. Now start putting the numbers together. 25% of AFA cadets will not commission. 25% of UPT students will wash out in the 1st phase of UPT. 25% more will wash out in the T-1/T-38 phase. Than out of those remaining 25% will get fighters. Basically 10% that start down the path will get a pointy nose airframe.
Although it is great to want to fly the fighters you also need to want to be an officer 1st. You will not fly everyday of the week, more likely @2x a week. You will be an officer though every day of the week. The days you are not flying in an airplane, you will be flying a desk in an office.
Additionally, being a pilot in the AF is a long term commitment. You will owe back 9 years after you wing. UPT is 1 yr. If you have to wait to start UPT for 6 -9 months after commissioning, than in total the 1st time you can walk will be when you are around 33 yrs old or in others words 2 decades from now.
Finally, as others have stated get good grades so you can clear the 1st hurdle. Move on from there, and always keep your options open as you clear each hurdle. You are not even at the letter A yet, and getting fighters is letter Z. You will not be at A for about 2 more years. Letter A would be applying for SLS at USAFA as a junior. How do you become competitive to attend? Good grades, lots of ECs, and a strong PSAT/SAT/ACT score. That is where your mind should be impo because those things are within your immediate control. Getting a fighter in the year 2025 is not in your control.