Steering Retrospec Speck 20"
I've never ridden one of these bikes.

I response to your question, I Googled to check it out. The reviews are not flattering.

But to answer your question, I see that the angle of the steerer and front forks looks very steep. I'm not surprised that it feels like you're all over the place. Combined with the narrow handle bars, it would take a while to learn to control it - so I do agree with your friend. 

Wider handlebars would help, but check that it still folds correctly with them on it before you pay for them.

If you can practice riding somewhere there is plenty of room, with time you should be able to learn to control it.

But if possible, I would return it, and invest the money in a better product.