So I was reading few articles on Quora and noticed this question,
I realised that no one actually answered this question properly with a satisfactory answer.
So here I am with an another Tik Tok tutorial on the same.

Short Answer!
Yes, You can shoot TikTok longer than 15 seconds. There is no minimum requirements to get this feature(if I am not wrong).
How longer can we shoot?
TikTok allows you to shoot a video of max 1 minute (60 seconds to be exact).
Can we shoot even longer than 60 seconds?
No, but if you combine multiple videos from the drafts or privates, you can create a video of upto 5 minutes. Which is I believe is sufficient.