Would this be a hard job to do it yourself? Changing door-handle and lock to smart lock

[Pinkyandtheose]

I live at home with an aging parent. I am seeing signs of dementia with her. She goes into my room, snoops, reads my mail, and takes things - hair clips, hair bobbins, reusable period undies, regular undies.

I will need to get a lock for my door. I live a busy life and sometimes it's hectic and sometimes the hours can be lock. The idea of dealing with keys every day doesn't appeal to me due being so busy sometimes. I know myself I will lose keys.

I am thinking about getting a smart handle and lock. Something like this from Amazon.

Would this be a hard task to change over? The current door and handle is old - maybe from the 80s.

If I buy a door handle, will it fit my current door and frame or will I need to buy extra tools as well.

I don't know much about DIY jobs around the home. I can paint, cut grass, build a bed and flat packed furtinure but I don't know anything else.

Would it be easy to learn how to install a lock like this on an older door? Or should I call a locksmith or a handyman?

It's fairly straight forward, BUT there is no guarantee that it will be a straight like for like replacement.
DH has just replaced out bathroom door with one that locks (previous occupiers obviously didn't believe in locking doors!), ND he had to make the hole through the door bigger.