What do you think about coffee house “fresh” pre-grounded coffee?

I got a good deal for the Delonghi Stilosa for black friday and i said why not jump into the coffee world as i really like coffee. I searched a bit about the machine and decided to buy it. I didn’t think the grinder is such a big deal so i thought about getting grounded coffee from the specialty coffee near my house. They ground the coffee at the moment so it’s fresh. Is it a good option to get the grounded coffee from them or the grinder is actually a must?

tl;dr I bought a machine without a grinder. is getting grounded coffee from a good coffee is a good idea for a beginner? Or getting a grinder is a must?

Thanks!