Is this common to my age? Please explain about my hairline. (Photos)

This is likely male balding rather than solely hairline maturation. You may wish to see a physician specializing in hair loss to review options for treatment.

Most men start to lose hair in their 20s.  Your pattern of thinning at the left and right side of the forehead is typical.  It doesn't have to be even on both sides.
You should see a board certified dermatologist to get a prescription for propecia.  It should work well to regrow your hair.  If you aren't able to see someone, try buying 5% minoxidil topical foam over the counter and use it twice daily.

Thanks for sending the pictures.  There are two components to evaluating temporal recession - one is the recession from the sides of your eyes to the middle hairline and the other is the side temporals.  In your case, it appears that there is moderate side temporal recession and likely normal recession of the middle temporal points and frontal hairline.  In addition, there is visible thinning of the temporal peaks on both sides (right greater than left) and recession of the upper side temporal regions.  As a result, you have lost side framing of your face and your temporal recession is more rounded.
An easy solution would be to consider side temporal and temporal peak hair transplantation which could fix your situation - likely 350 to 400 grafts on each side.  This is a more difficult hair transplant to perform, so who ever you chose, get someone experienced in these types of procedures.  The good news about side temporal hair transplantation is that the side temporal recession usually stops at a line parallel with the front of your sideburn, so you don't have to worry about recession behind the grafted areas.  It also effectively brings down the frontal hairline by connecting with the sides of your face.

Your biggest enemy is the progressive thinning leading to a balding pattern that is not evident at this point in time. The degree of thinning that you are experiencing would suggest that you should see a doctor who most likely will get Bulk Measurements of your hair to determine the degree of the thinning that you may be presently having. If the diagnosis is early genetic hair loss (the most common cause of hair loss in young men and you are probably following your father's balding problem), then the best treatment would be the drug finasteride which is highly effective in men of your age and may not only stop the hair loss but possibly reverse it. If you are developing a more advanced balding pattern the best test to get is the HAIRCHECK instrument test which will determine the Bulk Measurements of your hair and this will show, over a one-year time frame, how effective the treatment will be. Once you know this information, then you and your doctor need to develop a MASTER PLAN which will define what you need.  If you want me to determine if you are developing a maturing hairline or recession, start off by sending me good photos with your eyebrows lifted high so that the forehead creases. This will give me the ability to judge where your hairline belongs. Then send me photos in your worst light so that I can appreciate what you are seeing.