To make the diagnosis of a deviated septum can only be made after a thorough internal examination of the nose. The bifid tip can be eliminated and with a combination of a cartilage graft between the 2 cartilages or suturing the lower lateral cartilages together. Chronic sinus problems from allergies are usually cause from nasal polyps blocking the sinus passageways. A CAT scan of the nasal sinuses is required to make that diagnosis. Functional Sinus surgery, septoplasty, and cosmetic rhinoplasty will be performed at that same time one anesthetic. Rhinoplasty is one of the hardest operations to perform correctly in the entire field of cosmetic surgery, so choose your nasal surgeon very wisely based on experience
As you alluded to in your question, the nose is both a functional and cosmetic thing. It requires techniques to both improve your breathing as well as the appearance of the nose. Based on your photos, you would need both the internal aspects (septum) but also refine your tip by using both cartilage grafting and suturing techniques to create a more refined tip.
Aging is not going to make your nasal concerns worse. Nor is your skin too thin to have a successful tip rhinoplasty and septoplasty
You certainly have collapse and obstruction of your nostrils, more pronounced on the left side. This can cause persistent nasal obstruction and is compounded by a deviated septum. Given both the cosmetic and functional concerns you have with your nose, a rhinoplasty would be an appropriate procedure for you to improve your breathing and the appearance of your nasal tip. Schedule a consultation with a rhinoplasty specialist.
I agree that there is no particular aesthetic problem with the profile. The asymmetry of the tip from the front view as well as the worms eye view can be addressed by tip rhinoplasty. This issue should not be aggravated by aging.