Just be sure to sell them all before 2 real life days go by. If you can time it so you are selling your crops after a Mabinogi maintenance, they are usually worth more because it resets the supply meter, we have not made a detailed comparison ourself, but this is in the wiki and as too many people were growing pumpkins we know we got more for our cabbage than for our pumpkins. Tomatoes have the fastest life cycle so they are good for a first crop. We provide Mabinogi powerleveling for you to level up.
If you can spend some time at it the first day to get the bugs/water/fertilizer built up and restart something easy like tomatoes you should be ok. You do not need a huge amount of inventory. We have done pumpkins and cabbage and only needed 2x2 inventory space. Your crops go to your mailbox, you get them from your inbox, go to Blatt to sell them, and pick if you want a check or gold(mabinogi gold). You do not have to sell your harvest all at once, so you can sell a few, go shopping or put it in the bank, then go sell more.
