Is a 5:40 1600 slow for a female college runner?

That time is quite slow. Jenna Hutchins just did 4 sub 5s in her latest workout.

IMHO, you should be fine for D3, no need to worry about it. Enjoy the rest of your track season. Look up Summer of Malmo and (safely) build a big base over the summer. Run XC in the fall, enjoy the experience and don't worry about college track.

Here's an idea- during the summer & fall & winter, once a week, try to include something like 6 x 100m with the 1st 50m smooth accel, last 50m hard sprint. Over time, you'll likely develop more speed. Combined with another year of aerobic development, you may be able to run a significantly faster mile.

But running a faster mile should be connected to enjoying your senior season of HS track. There's plenty of time to worry about college track, when you're in college.

After graduation, another Summer of Malmo and you'll be ready for D3 XC. Tons of fun and good competition too. Smell the roses, enjoy the ride :)

It's neither slow nor fast. In the D3 conference I competed in, a 5:20 1500 would have ranked you ~75th in the conference last year. So you probably wouldn't be running at the conference meet, but you would be solidly in the middle of the pack at most invitationals. You should run in college if you want to keep competing. It was one of the most fun experiences of my life even though I was also a mid-packer.

For D3 those times would be mediocre, but not super slow, and being a junior in HS there's room for improvement.

With those times you would be an average D3 runner

It's not fast, but there's a place for everyone at the college level. I've had sub-5 milers and 6+ min milers that have both had wonderful experiences when they found a program that supported them and had academics that fit their needs. If you want to keep running, go for it! It sounds like you have a realistic level of your current ability and that's key to having future success.

You can get faster but that doesn't matter- if you enjoy running and competing- do it. You're realistic going D3, so have fun and you'll improve.

And one factor that even you may not be aware of is the quality of coaching.

I know people who weren't particularly "fast" in high school who went D3 and improved tremendously because their HS coach wasn't that knowledgeable and the college coach knew what he/she was doing.

Definitely capable of walking on to programs at nearly every level. Probably would be best at DIII level.

Maybe try NAIA. That might be a better athletic fit for you. I know a girl that was probably a 22 min 5k XC runner and she ran at some obscure small college. Got to travel the US. Got a degree. Got her name in the paper. Met lots of people. If you're at a D1 or even a D3, you'll possibly be an also ran and sit home while the rest of the team travels.

What's going on? These post are way too positive for Letsrun. But anyway, like others said, a 5:40 mile (21 mins on the avg 5k xc course) would put you about mid-pack for most D3 conferences. It's good to check out the meet results from whatever college you decide on to get a better gauge where you stand. However, with another year of high school and four years college, there's still plenty of room to improve to the the point where you're leading the pack.