Would there be a reduction in lift curve slope or any other performance (compared to a straight wing, with no sweep), for my wing with only sweep at the trailing edge?
1. Lift curve slope. Leading/trailing edge edge sweeps of 0° & 12° yield a quarter chord sweep of 3°, which is very little. When for instance using the simple sweep theory like in this answer, wing lift coefficient $C_L = c_l \cdot$(cos$\Lambda)^2$ reduces by (cos 3°)$^2$ = 0.997 = 0.3%.
2. Any other performance. Stall characteristics might be slightly improved, since the trailing edge will deflect the flow slightly in the wing root direction, so full aileron control in a stall. You might find more info in the answers to this question, although they pertain more to faster planes with higher sweep angles.
3. Structural implications.. The usual issues with forward sweep are increased tip torque and increased flutter tendencies, which requires stiffer torsional construction. But again, with a straight leading edge and only 3° forward sweep there should be no serious consequences.
Above picture (from Wikipedia) shows the L-13 Blaník. Quoting the Wiki article, it is the most numerous and widely used glider in the world. It has slight forward sweep for positioning the instructor not above the main wing spar, and has very favourable handling characteristics.