Hi,
Some moles do grow slowly in size with time. Look out for rapid growth, irregular borders, irregular colour and irregular shape which may raise concerns that the mole may be sinister. Ulceration and bleeding are also symptoms of concern.
A mole screening by your doctor/dermatologist will help allay any lingering concerns that you may have.
Your attending doctor will examine your moles using a magnifying lens to see clearly the clinical details. Suspicious looking moles are biopsied to examine the cells under a microscope to exclude a melanoma.
Hope this helps!