Mine does 90 minutes each way - and has done since Y1, since Y7 she's done it independently.
She doesn't mind doing it - 2 trains with a change of platform in the middle and a 5 minute or 3 minute walk at either end. She gets a seat on both, the long one has wifi and tables so she just does all her homework, or downloads Netflix to watch.
With where we live, the shortest commute to any secondary school was just under an hour but involved a long walk, so she prefers this for the school she wants.
The station staff all know her and look out for her (and sling left-on-board items off at our local station for her!) and she's very good at managing things like cancelled trains or other issues.
In terms of friendships, her school has a huge catchment as it's lottery entry, so it's not the case that she misses out on things happening locally. She seems to have a solid online social life and will then go into London for parties, meet-ups etc at weekends.
She stays late several nights a week for afterschool clubs, and has music classes externally that are close to school another couple. It's her normal so there's never been any complaints. She's a bit tired first week back after long holidays but after that it's fine again.
The plus is that with London there are loads of options if something isn't working or if she misses a train there will be another along in 20 minutes. Any of the more local options geographically there was just the one bus or nothing. She has a lot of freedom this way.