I need some advice!

There are a lot of factors that play into it. If you're looking to lose a lot of weight then yes 20-30 pounds is realistic in the beginning, however if not its going to be harder. I would say 30 pounds is pushing it. Your body doesn't have a deadline for losing weight, but the main principle is calories in-calories out. You can eat very little and up the exercise, but you risk gaining all the weight back afterwards. My advice would be to start at a level you're comfortable with and go with it. You'll defiantly lose weight in 2 months so you'll be feeling/looking better anyhow. (:

Welcome to MFP! If there's one thing that people here are happy to give, it's advice. Of course, you have no idea whether most of us are qualified to give it....

I would like to know if it is possible to lose 20-30 lbs in 2 months? 2 days ago I started walking 4 miles a day, if I do that ever other day would it work, along with eating healthy?

Weight loss starts in the kitchen, not the gym. As long as you eat less than you expend in (1) keeping your body going - your basal metabolic rate, (2) your ordinary daily activities, and (3) exercise, you will lose weight.

It's simple, but it is not easy. Some people find that they can lose weight by exercising and making better food choices, like cutting back on sweets and fried food, but most of us on MFP have found that calorie counting works better.

Exercise is important for a couple reasons. First, it lets you eat more--but it also makes you hungrier, so in that sense it balances out. But it makes you fitter and happier, which are two good reasons to do it.

I suggest that you start by reading this post:
http://www.myfitnesspal.com/topics/show/1080242-a-guide-to-get-you-started-on-your-path-to-sexypants

Once you've worked your way through that, there's more very useful information here:
http://www.myfitnesspal.com/topics/show/833026-important-posts-to-read

For what it's worth, I lost about 1.5 lb./week for my first 5 months on MFP, so about 6.5 lb./month. After that, I slowed down to about 1 lb./week. Now I'm nearly at my goal and aiming to lose about 2 lb./month until I'm there.

I did some quick math (as I work in metric) and 30 pounds is roughly 13.5kg.
When I did WW, they said that .5 - 1kg a week is a healthy weight loss. So, to loose 13.5 kg over 8 weeks, is roughly 1.5kg a week.
It's do-able, but you will have to really be strict about your eating (and ensure you eat healthy so you don't end up sick) and exercise.
Track everything you put in your mouth, and your exercise.
Good luck!!!

What's the hurry?

Odds are if you do it that quick, you're gonna gain it back.

You don't have a lot to lose. I'd say 10 - 15 might be doable

It all depends on how heavy you are to begin with. A general rule of thumb for weight loss, remember this:
The quicker it comes off, the quicker it'll go back on.