Inexperienced; are more quiet and 'boring' days/conversations normal?

So I've been getting to know this girl for the last few months. We started to get closer once we realised how similar we are in terms of humour, conversation and our personalities in general.

One of the things about us though is that we're both introverted. I do like this. In the past I have felt overwhelmed trying to keep a consistent energy up with some people. With her though it feels calm. Most of the time we are joking and laughing around, however, sometimes things are very reserved, and when we hangout or call while playing video games there can be silences, a less energetic feeling, us being much less flirty, and stuff. Honestly, sometimes I do worry she might be bored because of how laid-back we are on those days. We have also spent most days either hanging out or calling each other for 4 months straight, so that plays on my mind too.

This hasn't been helped by a mutual friend that has felt left out since we've gotten closer. He actually told both of us that either I'll get bored of her or she'll get bored of me. She confessed last week that his comment is on her mind a lot. We even had a situation where we didn't interact properly for a day because she thought I had gotten bored of her. She said she was going to bring it up, but she really didn't want to hear me actually say "yeah I'm bored of you".

So I guess it's one of those things that has been playing on both of our minds. But what is the general consensus on this? Is it a sign of incompatibility when we're having silences or 'boring' days this early? Should things always be upbeat or lively around a person you like? Or am I mainly overthinking basic things?