You need to look at your predicted grades these determine if you will be offered a place at the university. Generally schools put the predicted grade one above what you got at As level.However you have to consider if these are achieveable if you belive that you could get the A at Alevel then apply to better universitys offering AAA if you dont there is no point waisting your choices. It is also dependent on what Alevels you are taking 'soft' subjects such as media, photography, film studies, sociology, busness studies ect. will be fairly easy to get the A at the A2 however proper subjects such as Chemistry, Maths, Physics, Further Maths, History, Geography become far more difficut at A2 and this needs to be taken into accout when making your choices. You should always have a back up option and maybe a range of choices from AAB-BCC would be realistic just incase there are any problems you don't want to deal with the stress of clearing and maybe one AAA choice as an asperational target!