If you're not used to organising your own travel arrangements, then there's other things to think about which perhaps someone else has done for you previously:
Is your passport valid and up to date? You usually need it to have at least 3 months until expiry from when you plan to return. Do you need a visa and if so, are you sorted?
If you're taking hand luggage, do you have the right size for the airline you're travelling on?
When choosing your accomodation, are you thinking about public transport and convenience of getting to and from whatever your plans are? A cheap hotel on the other side of town might work out. more time and hassle than it's worth. Is your hotel convenient for other amenities you might care about? Also, as it's probably a crowded venue etc etc, make sure when planning your routes to take in to account the liklohood of delays/crowds etc.
what wil the weather be like? Do you need anything specific? Do you have the right travel sized items of your favourite toiletries etc?
How are you getting to and from the airport, on both sides? Are you comfortable with your options? How long will it take?
For the event, you will need your tickets etc. Do you also need ID and if so, what sort?
Do you have a bag that's safe to keep your valuable documents in - zippered internal pouch etc (x1000 if someone else has tended to hold your documents).
You say your mum has organised things previusly so are you quite young? It's briliant to travel when you're young, but it does mean you may well meet other people and get swept up in things. I consider that a good thing. But maintain the same level of street smarts that I hope you would at home on a night out!