Use moms credit card for broken iPhone screen?

I cracked my phone screen and my mom only knows of a small crack I had a while ago though it got much larger. Should I order an I cracked Diy screen repair kit online with her card and try to fix it myself or should I tell her and get in a Ton of trouble and ask to buy it?

Shall I get the 6s plus or 6 plus?

I'm feeling really overwhelmed. My parents said the 6s plus is too expensive and I should get the 6 plus. But this is my money I worked for so what do you think I should do? I feel worried £410 is for the iPhone 6s plus. I'm feeling worried and overwhelmed on what I should buy

Help me with this situation?

Okay so I'm a 14 year old who makes money via instagram and all the money goes to my brother s account. For the past month I have been saving up for an iPhone 6s plus 32gb. Its £400, and my bro is saying I shouldn't buy it and its a waste and i shouldn't buy it and that he won't let me. I'm about to buy it right now, do you think I should? I worked really hard for this and he said I should get the iPhone 6 or 6s since its cheaper but they are too small for me. What do you all think about this situation cuz I'm feeling very overwhelmed about this whole thing. Tbh I just want my phone. I don't know tho. I know this situation isn't that deep but please gimme answers xx