Nope. If your age minimum for a partner y is determined by your age x with the function:
y = 1/2 x + 7
then the point where y = x is at y - 7 = 1/2 x. Setting y to x leads us to x - 7 = x / 2, which happens at x = 14.
At x = 18, y = 18/2 + 7 = 9 + 7 = 16.
Relatedly, if we invert the function, y - 7 = 1/2 x, thus 2y - 14 = x, which gives us the theoretical maximum for a possible partner. If a possible partner is older than that, you’d be understood to call them a cougar, or whatever the male equivalent is.