Christmas Decorative Light-up PCB with Speaker Output

I'm an Electrical Engineering student at Georgia Tech in my sophomore year and this is my first custom PCB, which I designed as a light-up ornament. When the button is pressed 15 blue LEDs around the perimeter of the heart light up, and a recreation of the chorus from Beaches by Beabadoobee plays out of the speaker using PWM output.

The power system for the ornament is fueled by 2 AAA batteries (3.0V), which are fed through a boost converter to account for the higher forward voltage of blue LEDs. This power system also has a switch so it can be turned off completely/reset.

The MCU I chose was an STM32, which I'm clocking with an 8MHz crystal oscillator. The button and speaker are connected to GPIO pins in a standard configuration, and I've attached a 4-pin header for programming with an ST-Link. I'm planning on writing my code in C++ using MBED libraries as that's what I'm most familiar with. Also, to account for the current draw of the LEDs, I'm controlling them through a single GPIO pin with a MOSFET transistor as to not overload the chip.