A little late to the party, but this is definitely something I can chime in on!
Firstly, nice work on the training! Some weight and bodyweight training will do wonders for yourself and your riding, I've been doing powerlifting and olympic lifting for a while and its really helped me come a long way.
Over training is a bit of an over used and not-so understood term thrown around in fitness, but still worth considering on a personal level. Mostly, its trial and error, but what to take into account is fairly simple.
•How much physical activity you fit into your week (at home, work, training and riding),
•Level of experience with training and riding,
•Your schedule of where you slot your training in relative to your riding,
•Recovery time (mobility, stretching, nutrition and most importantly sleep)
Taking all that into account, if you ease into the training and give your body time to get used to the training and recover fine, keep ramping it up until you feel as though you're at a level you're comfortable with. The body is capable of a lot and will adapt very quickly, you'll reap the benefits in no time.
Happy trails!