What does it feel like?

Sometimes I feel like I can feel my baby kick, it varies in how it feels. One time I thought it might be a kick, is when it literally almost felt like someone just poked my stomach. And then sometimes it feels like a twitch in my stomach. At 18weeks and 4 days how low should I be feeling kicks? Is that even what it feels like, or am I just imagining it because I want to feel it? Lol im a FTM so I have no idea what I'm looking for!