Visually, hypermobility and flexibility look the same - they can fold and bend. However, mechanically, they're not.
Hypermobility is a laxity in a persons ligaments whilst flexibility refers to the length of the muscle fascia and nervous system.
We have approximately 900 ligaments in our body. Ligaments are tough elastic bands that surrounds your joints, connecting bone to bone, to support your joint and limit movements. Stretching or tearing them may lead to instability in the joint.
Flexibility on the other hand refers to the range of motion which is determined by the length of your muscle, fascia and nerve sensitivity. Unfortunately, our flexibility tends to decline as we age and can be affected either positively or negatively due to temepratures of the environment, fatigue, activity levels etc.
Hypermobility tends to stay constant throughout with minor changes due to age.
Ehlers-Danlos and Marfan syndrome is used for those with more severe hypermobility.
Joint hypermobility may present a few problems for some individuals such as persistent tendonitis, aching and frequent dislocations. Some people have a couple of hypermobile joints in their body and a small handful will have it all over their body (scoring a 9/9 on the Beighton Score)
Beighton Score
Personally, I'd go see a professional (doctor or physiotherapist) if you do score more than a 7 to help you understand your body better, reduce pain, joint dislocations and learn how to increase joint stability by muscle strengthening.