You are not kind of locked into an attachment style from the moment of birth or when you start to mature. People can still have fulfilling relationships and they might not even experience any problems but can still be characterized as being one of the three disordered attachment styles. How you relate to others is very much in your control although it might be influenced by factors that you cannot control like whether your caregivers were present or absent in your life. One study suggests that attachment styles, they just tend to become more secure over time simply because the older we get the less time we have for relationships that don't meet our needs nor make us unhappy.