J3SSiiCa --
I think sockmonkey gave you some great advice. To be healthy is better than being skinny.
Depending on your frame, anywhere from ~ 110-125 is your mid-point for a healthy BMI (body mass index). Take it slowly. If you lose it gradually, you will be doing the right things that will help you keep it off!
I lost 35 lbs over an entire year and have kept it off for 2 1/2 years now.
Remember diet is key, especially portion control. It is crazy how small serving sizes are -- when you have a medium bag of pretzels, there is usually 3-4 servings in there but it is so easy to eat the whole bag. If possible, eat 4 to 6 smaller meals a day -- this will keep your blood sugar levels stable and will never let you get too hungry...and more vulnerable for a snack attack

Also, I try to eat a substantial breakfast and lunch and limit my calories in the evening.
What you eat matters alot too. Read the labels and look up calories, fat grams and sugar levels online. The more you know, the better you will be able to make smarter food choices. In general, stay away from fried anything and sugar and white food (such as white bread, cakes, potatoes).
Physical activity is important as well. Not sure if you are active but start slow. Maybe walk with friends for 30 minutes 4 times a week for the 1st week. You can eventually progress to some jogging, jumping rope, maybe some light weights. I used to hate exercise and now I really enjoy it. I have a little 15 minutes routine as soon as I get up so I get some level of activity in every day but I try to do more later in the day as well.
One last thing -- keep a journal for both food and activity. I really helped me stay motivated and I could look back on what I did every week.
Hope this helps. Good luck and let me know if you have any other questions.