There is nothing wrong with getting 4 moles checked at one time. In fact, with your colouring you could book a 6 monthly all body check for the rest of your life. Make sure they check your scalp, between your toes and other areas that you can't easily see yourself. It's your life and at least melanoma is a cancer that you can see unlike most.
Yes you should get new moles checked especially as you have mentioned those dark one. There are excellent sites on the internet showing melanomas and describing the ABCD's to look out for. Who cares if the doctor thinks you're a hypochondriac. Won't you be going to a dermatologist or adult doctor soon enough anyway?
You are at the age that new moles do show up and having two the same is also a positive sign. Many of my moles change colour in the shower due to capilliary dilation. They also change with hormones (if you're a woman).
It is not hypochondriac behaviour to get new moles checked out.
Continue to wear sunscreen, hats, long sleeves etc.
If you find yourself obsessing over health issues then consider other options but get these ones out of the way first.
I think they are moles..You don't have to worry it can be removed by a dermatologist with the help of surgical excision.This involves cutting out the entire mole and stitching the skin closed. One thing more never try to shave off a mole at home. If skin cancer is present, much of the cancer can remain and possibly spread. Shaving it yourself also can cause disfiguring results and can cause an infection.