How Does Birth Order Shape Your Personality?

First-Born Child

Leaders
High-achieving (or sometimes even over-achieving)
Structured and organized
Responsible
Mature

parents have higher expectations for you and look to you to set an example for your younger siblings.

Middle Child

Independent
Peacemakers
People pleasers
Outgoing
Adaptable
Attention-seeking
Jealous
Competitive
Insecure

some studies have shown that middle kids are less likely to feel close to their mothers3 and are more likely to have problems with delinquency

Last Child

Outgoing
Fun-loving
Charming
Free-spirited
Immature
Manipulative
Self-centered
Dependent
Risk-taking

Because parents are sometimes less strict and disciplined with last-borns, these kids may have fewer self-regulation skills.

Only child

Mature
Diligent
Thoughtful
Perfectionistic
High-achieving
Imaginative
Self-reliant
Sensitive

If you're an only child, you may feel more comfortable being alone and enjoy spending time in solitude pursuing you own creative ideas

Dr. Lev suggests that the effects of birth order can differ depending on gender.

"For instance, in a family with two female siblings, the younger one often appears more confident and empowered, while the older one is more achievement-focused and insecure," she explains.

She also suggests that there is often a notable rivalry between same-sex siblings versus that of mixed-gender siblings. Again, this effect can vary depending on gender.

Communication

Firstborns and only children are often seen as more direct, which others can sometimes interpret as bossy or controlling.

Middle children may be less confrontational and more likely to look for solutions that will accommodate everyone.

Lastborns, on the other hand, may rely more on their sense of humor and charm to guide their social interactions.

Relationship Roles

Firstborns, for example, may be more likely to take on a caregiver role. This can be nurturing and supportive, but it can sometimes make partners feel like they are being "parented."

Middle children are more likely to be flexible and take a more easygoing approach.

Lastborns may be more carefree and less rigid.

Expectations

Firstborns often have high expectations of themselves and others, sometimes leading to criticism when people fall short.

Middle children are more prone to seek balance in relationships and want to make sure that everyone is treated fairly and contributing equally

Lastborns may place the burden of responsibility on their partner's shoulders while they take a more laissez-faire approach

While birth order theory holds a popular position in culture, much of the available evidence suggests that it likely only has a minimal impact on developmental outcomes. In other words, birth order is only one of many factors that affect how we grow and learn.

I am a middle child

almost all the facts from the article coincide with the story of my life except for two details: I am not a peacemaker and not a people pleaser

elder and younger sisters

speaking of my older sister and my younger sister, there are also many things that coincide except for two aspects:
the younger sister has self-doubt due to constant comparisons with her older sisters
the elder sister is very confident