Can you have what looks like a receding hairline at age 17?

Genetic androgenic alopecia can start with puberty so you may be seeing early signs.  You need to see a doctor for an exam if you want a diagnosis.  There is no way to completely stop genetic hair loss.

I am not sure what you mean by 'tapeline'.In their late teens and early twenties, young men's hairlines mature. Temporal recessions develop of varying depths and the hairline may elevate. This is normal. In men with genetic male pattern hair loss (MPHL), the temporal recessions continue to deepen, the hairline continues to recede, and density is lost to a varying degree in the forelock, mid-scalp and crown. There are medications to treat this but the first thing to determine is if you have MPHL so you might want to visit a specialist or just wait a year or two to see if things progress.If they do, you could try using minoxidil.

At age 17, it can sometimes be challenging to distinguish between normal hairline maturation and genetic hair loss.  A hair specialist can help sort out if one (or both) is occurring. The most likely explanation for chagnes in the temples at 17 is hairline maturation. No treatment consistently alters the normal reshaping of the male hairline between 16-26 years of age.  If genetic hair loss is present, then minoxidil, finasteride, laser and platelet rich plasma are options.