Am I a bad person if I do this

Story:
Hello people. I (23 years old) have a little moral/ethical dilemma.

My mother (45 years old) lost (better said somebody kinda stole her phone) about two weeks ago. I told our insurance about it but I told them, that the phone we lost was about 1000 USD worth instead of the 240 USD it was really worth today. We received 800 USD, so I gave my mom 300 USD and kept 500 USD for me.

I don't feel bad for the insurance, they have more than enough money so thats not really my problem. I just question if it was a good desicion to keep 500 USD to me. My mom didn't even know that we could receive some money from the insurance, since we come from Portugal and she doesn't know anything about the system where we live in and she would have received only 240 USD if I had told the trueth to the insurance company.

I am doing an apprenticeship and make almost no money and pay all my bills alone at the moment, so I thought about this idea to put the 500 USD to the side since I'm going to a school to learn french for two weeks which costs 2000 USD, which I will be paying alone. I do feel kinda bad since my mom pays the food and the house we live in.

In August I will start working fully and make more money so I will be able to pay rent with her and everything so I thought this was okay, but now I'm questioning my desicion and feeling kinda bad.

So I wanted to know what you guys think about all this. :)

UPDATE AFTER 1 HOUR:
Damn you guys are making me feel bad. I still didn't tell her anything so I can still give her the 500 USD. I didn't thought it was this bad. I won't have to show the insurance anything since I was kinda able to prove it and the case was closed, but that really doesn't matter.

I generally try and would say I am a good person, I just thought maybe this was okay for once or Idk, but maybe it's a bad place to stopping being the nice and moral one. I know it's my mother and I really do a lot for her and try to help her wherever I can. But hey who am I trying to explain myself to..

Thanks for the comments until now.

UPDATE AFTER 23 HOURS:
Thank you all for your honest opinions. Some people could have been a bit more polite, I was asking for opinions and not for a roast session and some of you went in haha. I told my mother about what I did to the company. She said it's okay now since I did it already but to stop doing that kind of stuff. I gave her all the money and do actually feel much better.
As I said, maybe not the best thing to lie to insurance but kinda their fold for not asking for a receipt of the phone or any prove that she really had that phone. I honestly don't feel bad about that Idk, call me a bad guy I guess.

Have a good life and thanks for all the replies.