Mark always gives really good advice, so you can't go wrong. But here's another option if you want.
Go to disc golf scene and find your home course.
Go check out past events, and compare scores for the average round of a tournament to your average score. Make sure you add a few strokes to your score to compensate for the high pressure situation.
So just as an example, my home course is Cass Benton in Michigan. http://www.discgolfscene.com/courses/Cass_Benton_Hills/events
My average round is around -3. My record is -11.
Here's the scores from a tournament held last year. Taking into effect it was a two round tourny, I would expect to shoot around -3 on any given day. So Open I would get my ass kicked, advance would be tough and novice would be too easy. So I would probably enroll myself in intermediate as my first ever tournament. Also, since there was only 7 people in novice, compared to 15/16 in advanced and intermediate. I would prefer the larger field myself.
However, I also know I've played with people from both open and advanced, and I know they are a bit better than me, but I can hang with them on my good days. So I would also make sure and take that into effect for later tournaments, but if it's your first tournament I would stick to something a bit more casual.
Open
Round 1: Cass Benton Hills - Cass Essential Shorts, 20 holes, par 61
Round 2: Cass Benton Hills - Cass Essential Shorts, 20 holes, par 61
Player R1 R2 Total Payout
1 John McAskin 53 51 104 / -18 $175
2 Geoff Bennet 52 54 106 / -16 $125
3 White Mike 56 55 111 / -11 $80
4 Dave Milewski 60 57 117 / -5
5 Jakkob Lammi 56 62 118 / -4
6 Austin Cook 66 67 133 / +11
Open Women
Round 1: Cass Benton Hills - Cass Essential Shorts, 20 holes, par 61
Round 2: Cass Benton Hills - Cass Essential Shorts, 20 holes, par 61
Player R1 R2 Total Payout
1 Sarah Demar 66 64 130 / +8 $95
Advanced
Round 1: Cass Benton Hills - Cass Essential Shorts, 20 holes, par 61
Round 2: Cass Benton Hills - Cass Essential Shorts, 20 holes, par 61
Player R1 R2 Total Payout
1 Ken Moote 52 61 113 / -9 $73
2 Matt Kora 55 58 113 / -9 $73
3 Chris Brown 61 55 116 / -6 $50
4 Kyle Greenhalgh 59 58 117 / -5 $35
4 Taggart Anderson 58 59 117 / -5 $35
6 Jon Kind 59 60 119 / -3 $20
7 Bobby Julio 58 62 120 / -2 $15
8 Tyler Kind 60 62 122 / E
9 Brian Merry 61 63 124 / +2
10 Jerry Chilson 62 63 125 / +3
11 David Dirmeyer 65 61 126 / +4
11 Jason Kirkaby 61 65 126 / +4
13 Phil Common 65 62 127 / +5
14 Jeremy Kemp 66 62 128 / +6
15 Daryl Ballios 66 64 130 / +8
16 Brett Styker 59 - 59 / -2
Intermediate
Round 1: Cass Benton Hills - Cass Essential Shorts, 20 holes, par 61
Round 2: Cass Benton Hills - Cass Essential Shorts, 20 holes, par 61
Player R1 R2 Total Payout
1 Josh Minard 56 63 119 / -3 $75
2 Lyle Downing 59 63 122 / E $57
3 Jeff Griffiths 64 59 123 / +1 $45
4 Eddie Ruiz 61 63 124 / +2 $35
5 Sam Smith 61 64 125 / +3 $23
5 Ted Bowersox 65 60 125 / +3 $23
7 Josh Cantor 62 64 126 / +4 $15
8 Michael Zanier 64 64 128 / +6 $13
9 Sean Blazo 66 66 132 / +10
10 Ryan McMann 68 65 133 / +11
11 Joe Willyard 70 64 134 / +12
12 Joe Biasutto 69 66 135 / +13
13 Brett Russel 66 71 137 / +15
14 Fred Vocino 69 74 143 / +21
15 Tim Thomas - - 0 / E
Recreational
Round 1: Cass Benton Hills - Cass Essential Shorts, 20 holes, par 61
Round 2: Cass Benton Hills - Cass Essential Shorts, 20 holes, par 61
Player R1 R2 Total Payout
1 Frank Raburn 57 66 123 / +1 $50
2 Bill Champman 64 63 127 / +5 $22
2 Chris Dulics 68 59 127 / +5 $22
2 Sean Morgan 61 66 127 / +5 $22
5 Derek Stockford 68 64 132 / +10
6 Shawn Boucke 69 68 137 / +15
Novice
Round 1: Cass Benton Hills - Cass Essential Shorts, 20 holes, par 61
Round 2: Cass Benton Hills - Cass Essential Shorts, 20 holes, par 61
Player R1 R2 Total Payout
1 Justin Goldsmith 64 67 131 / +9 $50
2 Troy Pope 65 68 133 / +11 $35
3 Russ Murer 63 71 134 / +12 $25
4 Jeff Lubin 69 69 138 / +16 $15
5 Matt Losey 75 71 146 / +24 $10
6 Michael Rocha 86 81 167 / +45
7 Kevin Martz 82 - 82 / +21
