Random beginner's questions

Hi there, I'm starting in this and I have a few questions.

1) It's difficult for me to actually take the fact that I could be dreaming seriously when I do a RC, mainly because my normal dreams are not much vivid. How can I fix this and also get more motivated?

2) In the strange cases that I realise that I'm dreaming, I wake up quickly and, as I said, they aren't much vivid. Is this normal?

(Sorry if my English is bad)

Both of those things are normal. You don't need to take your RCs 100% serious, just serious enough so that you validly question your reality.
Waking quickly from lucidity is also fairly common for beginners, and it's something you surpass with practice. Look into some stabilization techniques
as well (rubbing hands, spinning, noticing detail, etc)