The official NHC forecast doesn't go that far in advance, but it sure looks much closer than that to me. This is what I see on Storm Carib's 'how close can it get'.
Results for St.Maarten/St.Martin (18.05N, 63.12W): The approximate Closest Point of Approach (CPA) is located near 17.5N, 58.0W or about 339.5 miles (546.3 km) from your location. This is corresponding with the 120 hour position of the 5-day forecast (Wednesday, September 6 at 5:00AM AST).
Just for 'fun'... If the storm would continue on this track, the extrapolated closest point (X-CPA) is estimated at 18.6N, 63.0W or about 39.4 miles (63.4 km) from your location, where it can be in about 5 days, 23 hours and 20 minutes from now (Thursday, September 7 at 7:24AM AST, be aware that this location is not part of the official forecast and is prone to large errors).
40 miles away from a monster hurricane is WAY too close.