stop strerilizing

I sterilise the bottles as long as my kids continue drinking milk . Even for my 6 years old pre schooler . For my younger toddler, needless to say , I will continue as long as she still wants milk as she's pre matured , her immunity is weak . For me I just can't stand the fact that the bottles are not sterilise and I can't imagine all the germs going into their body . Maybe it's just me