Do you think my photography is good enough...?

[Winter Star]

I think your off to a good start but still need some improvements.
Your exposure seems to be off in some pictures. When you are shooting outdoors watch out for shadows and direct sunlight. Maybe invest in a reflector to help fill in the shadows. If you're working by yourself with no assistant a stand for the reflector will help.
http://www.bhphotovideo.com/c/product/52...l#features
You can also use a fill flash as well but reflectors are cheaper to start off with.
You have every right to be scared it's a lot of work to have your own business and keep it in the black. I think you should hold off on the studio and maybe make a spare room in your home into a studio. It's great that you are getting clients right now, but I think you still need to improve more til you can successfully start a studio.

You only need a model release when you are going to be selling the pictures to a company for an ad, you do not need one to post them in your portfolio. Do you have your clients sign contracts? If not there is a book on contracts by Tad Crawford. Or you can find some online as well.
http://www.amazon.com/gp/product/1581156...F8TQ1G5CF5
Your contract should mention that you own the rights to these and that you are able to use the pictures in your portfolio.
EXAMPLE
"The Photographer shall own the copyright in all images created and shall have the exclusive right to use the images and make reproductions for promotional or advertising material or for use on the Photographer’s website(s)."

Tip: In your facebook wall advertisement you say you offer wedding services but you have no wedding portfolio to show? If you have not had some experience in weddings I say take it off till you do have the experience. Wedding photography is a huge thing and can't be redone like an engagement shoot. Try looking into wedding workshops in your area. They cost a lot of money but it will help give you practice, tips and some shots to put in your portfolio. I also suggest redoing the ad because the pictures are not aligned properly and it just looks bad.

You still have some learning to do, keep practicing and learn from your mistakes. Look for inspiration from other photographers and see what they do different from you and learn how you can improve. Keep working on getting your business together and working on a website possibly. Maybe take a business class specifically for photography so when you're ready to start you'll have the information. This will cost a lot of money but if you keep improving and keep your clients happy, you can earn that money back.