Wearing a bra to bed is definitely all right but if you do go to bed, try to invest in bras that have some support. Because you are currently still developing, it might seriously affect the shape of your breasts and sports bra presses down on your breasts which restricts growth because they are rather snugly fitted (thus you wear them when playing sports for support). So try to keep sports bra for sports and a proper and comfortable bra (you could try bras with a good fit but not wired for sleeping if you feel uncomfortable when sleeping with wired bra). You need a normal bra to support your breast so that it does not start to sag at a young age. Hope that helps!