The main thing is to make sure the oil drain plug is tight. Then check the oil filter. High School dropouts at fast lube joints often leave the old oil filter gasket on the motor and then after several hundred miles all the oil suddenly blows out between the doubled up gaskets and ruins the motor. Didn't you have a mechanic check the vehicle over before buying it? You should have at least put it up in the air on a lift to check the exhaust for rust holes and the motor for oil leaks.

Its 13 yrs old. Some drips are normal. Steam clean underneath but not the top of the engine. Wait a few days, look for leak.

check the oil drain plug, check the oil level sensor, remove and clean the plastic under pan.

Clean the engine/engine bay. Degrease and detail it. Clean enough to eat off of. You will find the leak easily once it is clean. Might need to get under it and really get in there.

Remember to cover all electrical components and use a gentile stream of water to wash off the engine cleaner/degreaser.

I have a 2001 bmw 330i with a 6 cyl motor. I bought it about 3 weeks ago and I drive it then i park it in my driveway then the next morning i look underneath it and there is about 4 oil spots. One large one then 3 smaller ones. I've changed the valve cover gaskets already so its not that. I'm not sure if i should be worried or not but I need some advice! Any comments or input will be helpfull!