I've never done (paid) care work myself but my disabled mother has had carers for years so I am pretty familiar and have chatted with lots of them over the years. Good on you for doing this, it is such a worthwhile thing to do, you have the opportunity to make such a difference to people's lives. It's definitely more varied, interesting and rewarding than office work. The carers I have spoken to are to be honest a bit of a mixed bag, some love it, some find it OK and stick with it because the work/hours suits them, some really don't like it and only do it because they can't get another job - these ones it usually shows in the quality of their work TBH!
You do need to know (as I'm sure you've already gathered) that care work of any kind is hard hard work, with domiciliary care often you are pressed for time and need to travel around a lot so can be stressful, its physically challenging and it can be heartbreaking/emotionally very difficult too. It's also chronically badly paid. On the plus side the hours can be flexible and can work well around school pick-ups or other life responsibilities and you are absolutely doing a good thing for society, if you are a people person there are great opportunities for chat and brightening up someone's day!
Tips - no 1 is take really really good care of your back and knees. Make sure you have been properly trained in any lifting required and you stick rigidly to how you've been trained - you may think 'oh it doesn't matter how I help this old lady get up, she weighs nothing' but when you've done the same lift 10 times a day 5 days a week for a year, believe me your back won't thank you for not doing it properly!
If you aren't naturally good at relating to your clients/patients developing a good 'manner'/ 'patter' can be really helpful. Remember a lot of your clients even if they have family etc., yours may be the only friendly face they see all day so taking even a few minutes for some inconsequential chat makes the world of difference to them. For a lot of people, particularly the older generation, having to have carers is a difficult experience, they may feel they've lost their dignity/independence, they may have unreasonable expectations that personal care should only be done by family, they may not understand the difference between a carer and a cleaner/domestic/'servant' and they may have dementia or other mental health type issues - all this can mean they come across as withdrawn, prickly, needy, vague, confused, demanding, unreasonable or downright rude! You need to develop a good thick skin and consistent pleasant polite attitude with them, not take anything personally and hopefully (if you are able to) build up a good rapport and routine. I know it's hard but do try and treat them like adults/people, even where they are being awkward, too many carers just take a bit of a 'brisk'/patronising approach where they just want to do what they need to do as fast and with as little fuss or interaction as possible, I totally understand why as they're on a clock and have X many more people to get to that day but that as much as anything else can sap the dignity and individuality of the client.
If your agency is good you should have someone, a supervisor, manager or mentor you can approach for advice, raise concerns or simply vent to if you need to - if your agency doesn't do this I'd look to move to a better one, there is a strong market/shortage for carers in most parts of the UK so don't be afraid to swap agencies if yours isn't treating you right!