TTC #2 with Questions

Vivian • I`m 29, a wife, a mom of a 5 year old boy and an almost 2 year old girl, part time work from home teacher mom and a Christian.
Our first was a surprise with only 6 months into our marriage. I got pregnant with only a month and a half of missing the majority of my birth control pills (it was my first year of teaching- I wasn't focused on the pills). Currently, we have been off birth control for 1 year and a half using condoms/pull out method and have been seriously trying for two months. 
I may just be worrying but... Why was it so easy to concieve the first time? Should I just wait it out, try for the next two months with an ovulation kit? When do you think it is a good time to seek medical intervention?
I just may be stressing myself out. I just need advice on what steps to take.