Your mom will not be in the room with you. Every doctor is going to be different but they generally follow the same pattern.
When you first enter the actual exam room, a nurse of some kind will be there. They will take your height, weight and blood pressure. You usually also at some point have to tell them the date of your last period, but they will ask you of course. Then the nurse will leave you with a cup to pee in, and they will give you these weird paper like sheet clothes to cover yourself with because you have to take off all of your clothes (but you can leave your socks on! I always do lol). So you sit there and wait for the doctor to come in and you feel pretty awkward sitting there in your little uncomfortable paper sheet clothes.
When the doctor comes in, they must have a female nurse with them, regardless if they are a male or female doctor. This is done for protection. It protects you (to make sure the doctor does nothing inappropriate) and it protects the doctor (to make sure you don't claim the doctor did anything inappropriate).
So they do some typical doctor stuff first like listen to your heart, your lungs, and they feel around on your stomach. Then they ask you to slip off the top portion of your little sheet clothes so they can do a breast exam. While they are doing the exam they usually tell you how to do a self exam, how often you should do it, stuff like that. They will also talk about mammograms here if you're old enough.
So then comes everyones favorite part, the pap smear, or the pelvic exam. You lie down on the table and have to scoot your butt all the way to the very end of the table and put your feet up into these things called stirrups (Link). They will tell you to adjust if they need you to, like for example: scoot your butt down further, open up your knees wider, etc. This is where first timers feel the most uncomfortable I believe. Now your entire vagina is there wide open for them to see. It's weird at first but if your doctor is good they will make you feel comfortable. plus you will have a sheet over you so it's a little privacy thing to make it seem less awkward (like this).
OK so, now the actual exam, as if it isn't bad enough already...It has three parts. Also a side note, they should be telling you everything they are doing, or about to do, so there should be no surprises. If they are being quiet, ask them what they are doing, tell them you want it explained step by step.
1) External Exam - they will check out everything on the outside (including your butt! be aware lol :] )
2) Speculum Exam - Ok, so, this thing here is a speculum. It looks like, really scary but I promise you it's not too bad. It can be made of metal or plastic and this is the object that gets inserted into your vagina and opened so they can check out your vagina and cervix. So it will look something like this on the inside. Here is also where they perform a Pap Smear. They stick what looks like a giant q-tip to me through the speculum in order to get a sample of cells off of your cervix. This sample of cells will be taken to a lab, and will be tested for abnormalities. They can also do other tests here if you are having problems or are sexually active. If you are sexually active they will test for some STDs, or if you have a lot of discharge they might take a sample to test for yeast.
3) Bimanual Exam - They will insert one or two gloved fingers into your vagina. With the other hand, they will gently apply pressure to the lower part of your belly. If you do feel pain, it is important to tell them.
And that's basically it. If you have any questions, please ask them at some point during the exam. It's no sweat, as you get older it gets easier. I've had a ton of these and I do not think they hurt. If you have any other questions feel free to ask me.
(Some info was taken from - http://www.youngwomenshealth.org)