Should I practice?

You should practice. It's the only way to improve.

Practice. You'll feel better and may do a better job than you might think.

It's also good preparation for handling responsibilities later in life. If you don't get in the habit of doing so, it's almost impossible to develop the ability later in life.

I never practised and I got no where

Do you intend to improve as a flutist and musician? Or are you just in marching band for the trips and social fun? Posts like this make us wonder if you are lazy and unmotivated about other things, too. Nobody says you have to devote you life to the flute ( although I pretty much did) but you should learn to accept responsibilities and how to set and acheive goals. It is not the thing itself - it is the process. So pay attention to the work, practice, mark the spots that need reminders, and give this a true amount of effort. Do not just slobber thru once - give it a fair chance.

Practice. The instructor will hear every mistake. The fewer the better.

Dont be lazy, practice.

If it's for a grade you should practice.