The other side admitted liability immediately in my case too.
I hope you get dealt with much quicker. Remember - never accept the first offer.
Keep ALL receipts - for travel to doctors, hospitals, physio.
Prescriptions, phone calls, bandages - every blessed little thing.
Start a spreadsheet now - make a note of every phone call, every appointment, every piece of correspondence.
Make a 'timetable of event's - when the accident happened, who you spoke to and when, letters and correspondence - everything.
Make a 'pain diary' - log the pain every day. And inconvenience it has caused. Does somebody else have to do things you would normally do? Even washing up, if you find it difficult to stand at the sink.
Loss of earnings - if applicable.
It sounds a lot, but can be recorded simply without beng too time consuming - and will be invaluable when you get asked questions that need exact answers. 'How long did you take the painkillers?' etc.
Good luck with it all!