They can take 1 to 3 months, maybe a little longer indoors, but they are fast growing outdoors. I got a seedling from florida about 7 years ago and its about 10 feet tall because it was stunted a bit from being in a pot, but I saw its brothers and sisters this past year and they are happily growing and a good 20 feet tall now! So very fast growers, but they take about 3 years before the fronds start to split (They look a lot like a young coconut palm until the fronds split)
-Alex

Give the seeds a boost and place them in the hot water heater closet if you have one. It's usually the warmest spot in most homes. Don't place the pots directly on the heater, it could be too hot. Seeds need warmth and moisture but not sunlight to sprout. Keep the pot covered with plastic to keep it humid. Check on the moisture level periodically and when the do sprout, remove the plastic and give it filtered sunlight. I usually place potted seedlings under bigger plants which is how they grow naturally. Be patient with these seeds and don't dig them up! LOL