please help

I'm 15 and am questioning whether I'm straight or bi. I have never had big crushes on girls but always found them attractive but i have heard other girls say this. I'm just scared that I'll say I am bi and then not be bi and have people say I lied or something but I am scared that I will say I'm not and feel worse. I know it's stupid and probably nothing but I'm nervous in case I'm just confused and need advice literally and advice becasue I don't want to talk to anyone I know until I'm sure please help