i love my little puppy but I would say don't get one!!!
Unless you are willing and able to up your cleaning around the house by 200%, up your washing by at least double, be willing to wake up at 5am to take your puppy out to poo/wee, toilet train, not leave your puppy alone for more than an hour, have lots of chew toys lying around the house to avoid your furniture/possessions getting chewed, have a large ugly crate, spend money on insurance, vet, toys, bedding, accept the fact that for a while at least, you will have a puppy that poos and wees in the house etc, etc.
Is your mum really willing to take on a tiny puppy while you are at work....to toilet train it by taking it out every hour despite the weather, do some obedience training with it throughout the day, play with it, walk it, socialise it by taking it out and about etc, etc. A puppy is a whole different thing to a mature, adult dog.
It is a huge commitment in terms of time/energy/sleep and money and feels pretty similar to having a 2 year old human toddler in terms of time and effort.....
That said, I'm very glad we got our puppy but despite growing up around animals and doing loads of research about looking after a puppy, I was still shocked at how much time/energy and money it actually takes.
I don't want to put you off it would have helped if someone had told me the reality instead of just saying "a dog is for life"...which doesn't really help at all!