Is there much of a chance to become pregnant on day 17 of a 27 day cycle? Thanks

Yes, a small chance. Even if you have had a fairly regular 27 day cycle, the timing of your ovulation, the few days that you are "fertile" and your chances of getting pregnant may unfortunately vary from cycle to cycle . The postovulatory phase of your cycle usually lasts 12 to 14 days but the preovulatory phase may change. Monitoring your ovulation day will be preferable and more useful to you. Ask an REI doctor how.
Low but not zero. if you are wanting to TTC try earlier next cycle. If not wanting to be pregnant, day 17 is a bit late but no guarantees. Use protection if you don't want a risk. Best wishes.
You ovulate day 13. The prime fertility window is plus or Minus 3 days day but can extend to plus or minus 4 days so it is pussible,