Should I start charging for pictures?

I've been taking photographic pictures since 8th grade and I'm now a freshman in college (just turned 18 btw). Of course I'm still learning and I believe I have so much more to work on/grow. Well, I have a nikon d5100 w/ stock lenses and had it well over a year now after saving up; I've wanted a dslr since Christmas in grade school. I've been taking pictures of family and friends for free till yesterday I felt comfortable charging, a few family members & friend insisted. Well I just got a 50mm lense as a birthday present and shot a couple pics with it and I love it, I think it's great for portraits now. So I asked for $40 from two friends since they offered to pay. I just have two lenses, few memory cards, camera bag and thats allI. I also spend alot of time on photoshop/Lightroom too. I'm really critical on myself and my work so i've never had the guts to charge or anything like that. I want the true opinons of people outside my immediate friends and family members (i don't know if they're just telling me what they want to hear). With a whole bunch of pictures I've taken over the years I've finally created a portfolio. Can anyone please give me some opinions on my pictures and skills? And should I start charging? What do you think? Portfolio link below:

www.axduongphotos.weebly.com

Except for the off centered photos, I think you did quite well. Better than a lot of the photos I see on here.
I believe you have the eye for photography, you just have to work on it. No one shoots 100%.
I have the D5000 with the 18-55mm lens. And I've had several photos publish in local newspapers recently. Two of them on the front page.
Keep at it. You'll make it!