There a million things you can do to help.
You have already received the single best peice of advice, however. REST.
You are a novice, what you have done so far is fine. Hell, you can probably bench more than anyone you know. Now you need to cut it back a notch. Do each BP once every 5 days. At least one, if not 2 of those days should be an off day.
Simply doing this will produce enormous gains. When you learn how to focus more energy and intesity into each set you can cut back the volume, but for your age and for your relative length in time in this sport if you want to keep the number of sets its fine.
In another six months to a year, you'll want to cut back the volume more, training each BP only once per week. Don't jump ahead and do that now, you'll miss out on all those gains in the meantime.
Don't bother mixing up rountines (assume you have a solid foundation, and you do for chest). Its not necessary in the slightest until you get MUCH more advanced.
Most importantly KEEP IT UP! You have a great foundation, make sure you continue to learn and enjoy!