The structure you're concerned about is completely normal. It is the hymen or remnants of the hymen and all women have it to varying degrees. Sometimes it can become inflamed or protrude in which case it can be removed, but this is uncommon.
Based on the photos it appears to be normal anatomy. The bump you are concerned about may simply be part of the normally redundant tissue in this area. I would recommend a physical exam by your gynecologist or family medicine doctor for peace of mind. Good luck!
Internal exams are best done by gynaecologists
Your genital area appears quite normal but you should see your family physician or a gynaecologist.There are huge variations in the size and shape of the genital area amongst women. However, for reassurance, you should see gynaecologist for a physical examination.
Although it is difficult to tell conclusively from the photos submitted your anatomy certainly does appear normal at first glance. However if you are still concerned it is always worthwhile to follow-up with your gynecologist for an exam.
What you are questioning appears to be normal vaginal anatomy. To confirm, I recommend a quick visit to your gynecologist. Glad to help.