Hi, I am very new to cars. I bought my first ever car last month and recently I checked the oil and realized that I need an oil change. So I went to walmart, bought the necessary oil and oil filter and ramps to change it on my own. Only to realize that I may not have the right tools to open the valve. I had a 16mm open end wrench and no matter how hard I tried, I couldn't get the valve opened. I even tried hammering as suggested by some youtubers. No luck. What can I do? Also, there is a surprising amount of oil leaking from the bottom of the oil pan. Whats the deal with the leak? When I drive I don't see any drops of oil on my driveway. Any idea and suggestion to fix?