Listen to your body. When it is time and you go into labor it feels like your period cramps but stronger. Also take your prenatal vitamins daily and listen to your doctor. Congratulations and best of luck. You will do good.
Also, make sure that you have a good support group. One that will support any decision that you make for you and your baby.
If you start feeling uncomfortable when trying to sleep or rest, a body pillow will be your best friend. Also, mama bees belly butter and olive oil helped me minimize the stretch marks.
Good luck! :)