No, Second does not denote "not that good"!!! As the others have said, you generally don't have as many high notes to contend with, but not everyone enjoys counting ledger lines anyway. You will have a more varied role than you would as a First. You'll probably do a mixture of playing:
- Melody, often together with the Firsts
- Counter-melody
- Harmony
- The inner texture and body of the orchestra (admittedly, sometimes it can get a bit dull playing the "cha cha" of the "um cha cha" accompaniment in Strauss waltzes and the like, but the piece would sound completely naff without it - it's essential!)

Soap box alert!
I feel very strongly that Second Violin is not a lesser role but one which has different demands. I can't bear the inferences of the phrase "playing second fiddle". It's unfortunate (but frequently true) that the less advanced players tend to be put in Seconds in amateur orchestras. Look to professional orchestras though, and you will find that Firsts and Seconds are equally strong players, and their salaries usually match too.
Anyway, back to you. Orchestral playing is a whole new journey, and your skills in sight-reading, following, listening and (dare I say it) miming will develop, as well as your playing. It can be jolly difficult, but it can also be exciting and hugely rewarding. It's great that the emphasis is on learning and fun, but be prepared to work hard. As a Second you are sitting right in the heart of the orchestra, and the sound there is fabulous. Enjoy yourself.

And do report back.