Amateur Photographer trying to fool me?

Some Amateur Photographer trying to fool me thinking I'm stupid. She says "Buy the smallest lens for your DSLR and Nikon is only good for indoor"

Smallest lens? Seriously?
I have a Nikon D5000 I only got the kit lens, is she just trying to trick me? (She wants to be professional)
What's your opinion on this 'Photographer' and what should I really use?

That amateur photographer is clueless about what she's saying. What you quoted her as saying makes ZERO sense. What does she mean by "smallest lens"?

I doubt she'll ever be able to become a professional, judging by the grossly inaccurate information she put forth.

I can't advise what to use, because you haven't indicated what you're trying to do photographically.

Most blow hards say things like, "I only use prime lenses". Or "I always shoot manual." Or they put useless filters on their digital camera lenses to "protect their investment". Or they use flash diffusers. Or they buy a $5000 camera under the false belief that it's the camera, not the photographer that is the key to excellent photos. So I don't think your friend has even advanced to this level. Her statement is essentially nonsense. The physical size of a lens has little to do with its optical merit. In fact, larger lenses, because they have larger apertures, are usually better. But there's no hard and fast rule. As for her opinion about Nikon, do you think that Nikon would be considered one of the two highest regarded camera systems if they didn't work outdoors? Try to run that line past National Geographic.

You have a good camera and a good lens. Work on your skills. When you reach a certain level, you will know how to expand your gear.

I don't get you, really. But maybe she meant using wide angle lenses. They are light weighted and give a good view for many artistic purposes