If I took one ibuprofen earlier this morning at around 11 or 12 and I just took one at 10 at night, can this be dangerous?

No, but . . . Read the dosage on the bottle and the other info there. This is likely safe, unless you are on medications or have a condition that would not mix with ibuprofen. Always take ibuprofen with food to avoid an upset stomach. Although don't take any medicine with milk, yogurt or lots of cheese as these can coat the stomach and prevent absorption of the medicine.