Is it normal to feel small to artist friends

you're your worst critic.

it is called an inferiority complex.
You suck! ( it's just some negative reinforcement)
You suck! ( I am just doing it for you, I want you to do better)
You suck! ( This time I really mean it, this painting sucks ass. It lacks your usual sense of perspective and the colors are heavily in contrast with one another, it is like seeing a raw egg splattered on a manet.) You suck!

As an artist, or really any kind of creative worker, a person is bound to see where their failings are before their successes. They recognize their weaknesses best, if they are skilled. You see things in their work that are better that what you did. That's normal; nobody's perfect, and everyone's different. Everyone has different grasps of spatial recognition and anatomy and all the other important aspects of art.

You'd be best served recognizing where, specifically, you find their works better than yours. Then, learn from them in these areas. The most important thing in art is the effort you are willing to put forth to improve, so don't feel bad if you spot something they do better than you. View it as an opportunity, and learn from them. They may surprise you and ask for your help with things in return.

Just try not to compare yourself to them.

This reminded me of a great definition of artist that hit me like a ton of bricks when I first read it. It was me, maybe its you. Per Ken Rockwell, about photographers, but is applicable to all:

"An artist fixes his imagination in a tangible form called a photograph. He captures the spirit of place or person, real or imagined, in this photograph and the viewer responds to this.

An artist is a complete master of his tools. When creating art an artist transcends common existence as his spirit flies up to meet that which he is capturing. He may practice and learn his tools while he is not creating, however when creating the camera becomes an extension of his mind. No conscious thought is expended on the technical issues with which he is a virtuoso while creating photographs.

To make a musical analogy, a musician may woodshed his scales, but when he's jamming he's not even thinking about fingerings. He's lost in the passion of the moment.

Just like professional surfers who have a dozen boards or pro guitarists who have 23 axes, an artist may have a slew of cameras, each for a different purpose.

Likewise, other artists may only have one camera, or none at all. It just doesn't matter.

Artists sometimes dress funny and tend to stay up late. They usually prefer to photograph attractive young women and are proud of it.

No one ever sees their work since they have crummy ability to promote themselves, and sadly, usually don't even appreciate their own excellent work. Those that do drop down to Whore, which sadly and paradoxically means you will never see the work of a true artist unless you know one personally. Good artists are usually too embarrassed to show their work to anyone unless you are intimate with them, since their work is their soul.

Artists use any sort of camera, including pinholes and disposables, or 8 x 10s. They use whatever instrument they need to create what they want."

It's normal. When I take art classes, I'll go around and compare my work to others. I more or less feel better about my art, but the thing with classes is that everyone is at a different level.

Some of my friends are very talented. When, I see one of my friends work, I always feel inadequate to her skill. But my inadequacy has made me want to get better so, that I can draw just as good and be better with my art overall.

Use your emotion on this to fuel your passion to get better.
Good Luck:)

There will never be a good self critic; even these that we call "superior artist" wouldn't critic their own art as good or bad.