This is not a well cut stone. Take a look at other threads for recommended proportions. In general, stick to the following to get a well cut stone:
Crown angle: 34-35 (up to 35.5 if Pav is 40.6)
Pavillion angle: 40.6-40.8 (up to 41 if crown is 34)
Also please be sure your girlfriend is on board with a lab diamond for her engagement ring. Sure, you can get a bigger lab diamond than a mined diamond for the same money, but if that’s not what she is expecting or hoping for, it will be a waste of that money.