My DS has mild CP, he's diplegic rather than hemi, so both his legs are affected and he has a slightly weak core.
He was diagnosed at 2, and you are (understandably) asking the exact same questions as I asked.
He has had - Botox, AFOs, tendon lengthening and the usual physio. He found night splints preferable to day ones after about age 7. We tried to do a bit of daily physio, just a bit first thing and evenings and I really tried to keep up with this. Trampolining was a brilliant exercise for strength and core as was swimming.
To put your mind at rest - he's 21 now, drives a manual but finds an automatic easier, works a fairly physical job FT, has a bit of moderate pain at times, doesn't do much physio, has a lovely girlfriend, gets a bit more tired than others, can't really 'run', has a slightly noticeable different gait, isn't remotely bothered at all by his CP.
I was so worried the whole of his childhood about how things would be as he got older and no-one could (or would) ever really say. The one thing we tried hard to do was to keep him ambulant and out of a wheelchair. As an adult he is pleased we did that although he does use a mobility scooter at times
(Really rarely, more like Madge from Benidorm I'm sorry to say - if you don't know the programme, Madge is quite old and uses a mobility scooter on holiday, because she's on holiday and doesn't want to walk!! DS is a bit like that, rides the scooter, swigging beer from a can
). I keep trying to encourage him to take up Pilates now, for core strength and flexibility but haven't persuaded him yet.
His CP hasn't ever stopped him doing stuff he wanted to do - he's never skiied, but says he's never wanted to, same with football. In fact he pretty much stopped games/PE at school around 13. Not ideal, but he is incredibly strong-willed and wasn't going to do something he didn't want to do/couldn't do well. School were very understanding.
Please be reassured by all this and all the PP's answers - your DD will be ok and the treatments and help are getting better all the time and you don't have to spend hours and hours on physio, but some is a good idea.
I hope all this helps ☺️