I had my own doubt about my art for a long time after having heard similar comments from close relatives so I painted under a pseudo name and didn't invite any 'real' people in. Only online visitors.
I eventually got to the point that I like what I am doing and I could ignore my own well meaning husband's comments. (It's just not my style, i don't understand abstracts, maybe you could paint bigger? etc...) I have adult children who did encourage me which helped. Then facebook made me add my last name to 'Sunny Avocado', so there went my anonymity.
I realized only recently that I have always been an artist. After a trying childhood, I remember I would enjoy my alone time with a book full of patterns that I would use colored pencils on for hours. I was 15 or so and confided in a family member that when I was in a conversation that I would 'paint' the other person's face in my minds' eye. Shadowing and highlighting with absolutely no classes ever taken...no encouragement. As a matter of fact, after confiding this, I was shot down hard and put in my place by this family member. So I didn't dare again and forgot about my aspirations.
Years (and years) passed and during them I would paint rooms and exterior of my homes just to play with color. Color with my kids, and many, many art forms in 3d. I worked with glass, wood, cement, you name it. And it was fun! But then the same family member, all these years later, put a paintbrush in my hand and said "you can do it!" So I did.
That was about 5 years ago. I haven't looked back since. But you see, art was in my blood!