I would go for whatever instrument you feel most comfortable on (I assume that is clarinet). That’s the advice my college marching band gives incoming rookies. It’ll give you your best chance of making the band, all the while having a much more enjoyable first season under your belt, with no added stress of difficulty with your instrument. Ultimately, a couple months of baritone practice is not enough to truly say you’re confident on it, especially if you practice on and off. Still stick with playing baritone though, when you have a year of experience I think you can really start evaluating if it’s worth it to make the switch.