Based on the photo there are several issues here
1. The client is a hard user. Her finger tips show thick sidewalls from repetitive force, likely uses her hands a lot for work. This means there will be a lot of force and use on the nail. With this additional new length you she will end up with a lot of leverage and likely suffer damage and lifting. This client should have shorter nails
2. The thick and deep sidewalls indicate the nail unit is growing rapidly to recover from damage. I would not be surprised if also a nail biter. Likely there is a lot of cuticle that has been missed during prep which is a guarantee of lifting.
3. The deep sidewalls have made zone 3 very hard to get a clear margin, as Pure has mentioned there is some touching of soft tissue with the application. This is also a guarantee of lifting.
For this client I would prescribe a shorter length enhancement until the 'grow' into the additional length. Ensure a very thorough prep (dry cuticle remove AFTER wet work will likely show a lot of missed cuticle)
Be very careful to ensure a clear margin and zone 3 blend very carefully with a thin board that can really let you get it smooth and cleanly blended.
This client should also have a very strict daily cuticle eraser and cuticle oil routine to add a sense of value to the nail so they learn they are 'jewellery' and not tools.
Good luck. This will be a challenge for you