The mileage has little influence on whether the car will be 'fine' or not.
For example, I'd rather buy one with 150,000 miles on the clock that's spent its life in the hands of a salesman running up and down the motorways, has been well looked after and serviced on time, than one thats done 50,000 and had the tits ragged off it by a boy racer or someone screwing it round town.
Don't focus on the mileage too much. Look at the general condition of the car. Check the MOT history on the VOSA website, check the service history, any mechanical work that's been done etc. Do a HPI check. When you view the car insist on the engine being cold so that you can start it from cold. Make sure you test drive it, accelerate and brake hard to identify any issues if there are any.
The proof of the pudding is in the eating - I bought my 59 plate A3 in September 2013 with 90,000 on the clock...
Good luck