Congratulations! I'd say that counts as a lucid dream. Even though it didn't last long, it's still a big step toward having more lucid dreams.

You should do RCs as often as possible, both in your home and at other places regardless. It seems to me like not being in your house would be a difficult dream sign to keep up with. If you get into the habit of RCing throughout the day, especially when something seems strange, chances are you'll also RC in your dreams.

I'm pretty sure it's possible for your dream signs to change at different points in your life. When it comes to dreaming, most things are.