Lots of people go over the bars in boats of that size (or smaller). I have a 19' Stryker and go out all the time. I'm sure a lot of the other folks that are more experienced than I will chime in, but I'll tell you a few things I know.
1.) Start out on the better bars on the coast. Coos Bay, Winchester Bay and Newport are some of the better bars. Avoid shallow bars like Tillamook and Nehalem (others?) until you gain some experience.
2.) Read the tide book. All bars get rougher when the tide is ebbing (flowing out). The bigger the tide change, rougher the bar. Try to plan your trip so you cross on the slack portions of the tide (time between out-going and in coming) or when the tide is in coming. I think the safest plan is to cross at a low slack, this way you can come back in anytime before the high slack (about 6 hours). If you go out towards the end of the out-going you may be stuck outside until the next low slack tide.
3.) Look at the marine forecast. Here's a site I use
http://www.nws.noaa.gov/om/marine/zone/west/westmz.htm. In general I only like to go out if there's combined seas of less than 8' (i.e. 6' swell and 2' wind waves), less is much more comfortable. Until you get a feel for it you may want to look for combined seas of less than 6', actually being able to look at the ocean and get a feel if it's relatively safe takes time. Look for the trend too, sometimes the prediction can be off.
4.) Get a good VHF radio and GPS if you don't already have them and learn to use them. Make sure all your equipment (motor, bilge pumps, compass etc.) is in top notch working order.
5.) Try to hook-up with someone from this board who has ocean fished a lot and is experienced on the bar you plan to cross. Keep it short your first trip, near shore bottom fishing or salmon.
6.) Stay tuned to this site and learn, learn, learn. Ask questions, people here are happy to help out.
I'm sure I left a bunch of stuff out, but I think I'm starting to ramble.....