62 and 28 are excellent times.
With that kind of speed, and your 5:17 for a 1600m as a freshman, I am not sure why you don't think you will break 5 in the 1600m this year. I say that even though breaking 5 minutes is a "gold" standard for HS girls in the 1600m,
I was a half-miler who could run the mile, two-mile and CC, so I thought my example from my sophomore year would help assure you, but a girl who runs 4:35 would be one of the top 20 of all-time.
1. Our team did one long run on Sundays of 1 hour at a pace where we weren't short of breath.
2. Also did runs of 5-7 miles with builds of about 1/2 mile to a fast pace, which we held for about 400m, before slowing down again. This pattern was repeated several times in the run.
3. In addition, runs of 4-5 miles at a good pace, but stopping 2-3 times and doing 4 sprints of 100m with very little recovery.
4. As to the speedwork, your speed should allow you to run fast intervals.
5. Moreover, once you are below 60 seconds for the 400m, you should be able to run 65 or less on the way to a 600m in a time trial. It is usually best to push the 400m, and accept that the last 200m will be a little slower and require a strong effort to not slow too much.
6. You might also post an excellent 800m this year, especially if your 200m time dips below 28.
Every second off your 400m time, once you are below 60 sec, will show up in the other intervals, and once you are running much faster interval workouts, it also shows in a faster pace in the longer runs.
After your 800m is quite fast, and it appears that it will be, within a month you should be able to run the fast mile.
If in racing season and your 400m and 800m are good, expect to run first 800m of the 1600m about 8-10 seconds slower than your best 800m. This pace will not diminish much on the way to the 1200m, and the last lap will go well and probably you can kick the last 200m.
If someone runs 15 seconds slower that their best 800m for the first 2 laps of a mile, and your times are fast enough that this measure is appropriate, that person is running too slow to achieve their best time, but that runner can expect to run a fast last 400m.
For example, Ron Wartgow won the IL mile in 4:07.8, but he had run 1:52.6 for 880y in April, so when the first 2 laps were only 2:05.5 for the leaders, Wartgow was almost 2:06 and ran the last 880y under 2:02. I wasn't in that race (I was in the 2-mile relay), but I watched and I had raced Wartgow many times because he was in the same conference.