Group Finder is fine 90% of the time, but an alternative is either join a guild or if you are in a guild tell an officer you want to run an Ops. We set up runs all the time in our guild for first timers. Way less frustrating especially if the guild know what they are doing. We often just run SM EV and SM KP back to back on alts with first timers. Hell on my alt they skipped SM and did HM EV and HM KP, she was geared less than you, but I had been through both many times on my main healer.
Nothing much against group finder, but a guild run is a safer run for a first timer (expect way less knowledge on your part), never seen anyone kicked from a guild run and you are more likely to get more gear from a guild run.
What if you're new 50 in recruit gear?
To me it would depend on the rest of the group and your role while considering the rest of the group. However, if you were a guildmate, I would take you provided you at least had your matrix cube (I want to know you have at least put some effort into gear and not just expecting the group to carry you. The cube is easy and fast, but I can't believe how many new 50's don't take the 30mins to get it. )