Read Selly Oak Reviews
it's not as bad as everyone says. there's plenty of options for takeaway or drinks, and it's cheap and easy to get to nightclubs on broad street or in the city centre. public transport is fantastic - £1 bus into the city centre if you show your uni ID or about £3 on the train with a railcard and that's quicker than the bus. Aldi and big Sainsburys have lots of stock.
it looks like an average british student town with takeaways, an aldi, tesco and sainsburys on bristol road. I've been out at night on my own before and as a woman I didnt really feel scared at all. selly oak station has trains to new street every 15 minutes. the new retail park is so cool - the sainsburys is absolutely huge and if you're bored on the weekend, literally just go to sainsburys because it kills time and is actually so fun.