If you have them, you’re in good company. About 90% of women will get them sometime after their sixth or seventh month of pregnancy, according to the American Academy of Dermatology.
If your mother had stretch marks, then you're more likely to have them too, since genetics plays a role. If you have a lighter complexion, you will tend to develop pinkish stretch marks. Darker-skinned women tend to get stretch marks that are lighter than their skin tone.
Try not to worry, most will fade with the passage of time after you have baby. Whether any cream, lotion, or potion does anything is arguable.
If you have given it 6 months after baby and they are distressing you, then a dermatologist may be able to help.