Considering what you mention you should have (1GBps), those speeds on your phone & your mom's are not normal at all. Sounds dumb, but unplug the gateway for 5 minutes & then plug it back in.
Make sure that your gateway is not at floor level (the higher the better) & nothing is blocking its signal

I'd recommend trying doing a test with a different device (maybe a cellphone or other laptop), just to discard if the problem is with the provider (network or device: gateway) or the wifi module/board in your laptop