It is highly probable because you are most fertile about midway between periods. Most cycles average around 28 days (maybe 23-30 as a range). Most women are fertile around days 14-16, but also remember sperm can stay viable (alive) for up to about 3 days, so even if you are say at day 12 and not fertile "yet", the sperm may live another few days until you are fertile. And just an FYI, douching or bathing does not "wash" them out, it tends to propel them further up the vagina instead. Hope the info is helpful.
Edit: If trying to conceive, it is also recommended trying to have sex only every other day. (remember I said the sperm still are alive). Sex too often can lower the male sperm count and actually decrease chances of fertilization. Also remaining lying on your back, and avoid urinating immediately after sex are simple ways to 'aid' the process of fertilization along.