Yes, its normal. Don't worry they will all start ripening soon. Personally I remove any tomato that has any color at all. By doing this I stop any future calamity such as birds, racoons, possums and caterpillarss from taking a bite out of my fruit. The fruit when picked early will ripen indoors exactly the same as on the vine and don't believe anyone who says it doesn't. You can leave a tomato on the vine until it shrivels and falls off but why would you?