I would ask yourself- how do you feel? When you're eating 1700 calories, how are your energy levels? Are you able to get through your workouts? Do you feel like you're suffering and starving hungry? Depending on your answers, I think you can get a pretty good idea of how you're doing.
Also, your scale and measurements don't usually lie (over a long period of time) so you can look at those to determine how things are going as well.
I don't think 1700 is too low- but, if you're worried- why not start out a little higher for a little while and if you aren't seeing results- lower your calories OR increase exercise.
I think a lot of weight loss is about trial and error and finding out what works best for you

hope that helps and good good luck!!